I'm not totally saying it's Partridge... I've read that lots of people hate zombie theories about Brett. I only want to focus on what we know about RJ.
We assume that, like Patrick says, Roy Tagliaferro and Red John are the same person. Ok, so Rosalind Harker made a description of Roy. We can trust or not, but Patrick seems to trust her, since he asks her if Timothy Carter is Roy.The description says that Roy Tagliaferro is just under 6 feet tall, short straight hair, not muscolar, but not even soft, strong hands. Like I said we can trust or not this description, cause Rosalind is blind and above all she is fond of Roy.Then we can suppose to have seen him in the eighth episode of the second season, when Rebecca died with the poison and she smiled as a dreamer when she sees that man. We can suppose he is Red John. He has short dark hair and a desordered walk.In 2x23 we hear his voice for the first time. He modified his voice, but it doesn't seem a deep voice. Maybe a nasal voice.We know that Red John is related with Visualize. He worked in the farm in 1988. The priest said that a Young guy made the smile in the farm. So we can assume that now Red John is 45 or max 50.We had another description by Sophie Miller. Red John is a phobic. He's middle aged, good health, no family but many friends, great speaker, good posture and excellent whistler.And above all, we know he shook hands with Patrick. So...Brett Partridge: I admit it... I think he could be perfect. He fits Rosalind description, with the voice... He's intelligent, even if he seems a fool, cause he talked about Dickens and other stuff... I think he could hide a hidden personality. He died in 6x01. I'm not going to talk about zombie theories xD, but would it really be strange if Partridge faked his Death with the help of Tiger Tiger or all his friends? I don't understand why many of you think it could be so strange. It could be plausible. I love Jack Plotnick as an actor and I would be ok if Partridge didn't die.
Gale Bertram: No similar voice, no short straight hair. I think he's too tall. He calls someone in the 6x06 to inform about Jane's plan. Smith argued with him about what Jane knows in 6x02. I think he would be one of the worse Red John (my opionion).
Reede Smith: I like very much Drew Powell, but I wouldn't like him as Red John. He's a little bit too fat, way too tall and also quite Young. And I don't like the fact that he appeared in season 5. I would like that Red John was there also in the first seasons.
Ray Haffner: Good points for him. He fits with the description. He has the phobia of spiders. Good looking enouth to charm people, above all girls. The voice doesn't really fits. I think he's a bit too weak. But I support Partridge XD, so also Haffner could hide another personality. Perfect age and member of Visualize. He doesn't have the tattoo, but we have to study better the meaning of the tattoo. Maybe Tiger Tiger have the tattoo and not Red John.
Bret Stiles: Talking about personality... he would be perfect. Not really fitting with the description and with the voice, but I would accept it, beacause of the great carisma of the character. But... he's way too too old. He could be the father or better the mentor of Red John.
Bob Kirkland: He also died in 6x04. But he was kinda perfect for the description and the voice. And Kevin Corrigan made a great great work to describe the crazyness of the character. But he was a "good guy". I don't exclude the twin Brother. Maybe the person who saved him was Stiles and not Red John. But... Michael didn't shake the hands with Patrick.
Thomas McAllister: Xander Berkeley is sooo cool ahahah. I love all the Actors. The voice is too deep, but phisically he could be ok (not with the colour of the hair). I would accept him as Red John, but I think he's only a Tiger Tiger.
So... I would accept everyone but Bertram and Smith ahahah. But they seem to be the remaining suspects :( .
A question... why Red John would have put the bomb in the house if he was there too? He could have died in the explosion. Ok the theatrical part, but it would have been too Dangerous even for Red John being in that house.
 

Ok, I have a really short theory.

The only person who knew a single name on the list was Teresa Lisbon in Red John's Rules. Patrick tells her Gale Bertram is on the list. But why does Patrick stop there? Because Roddy Turner shows up and Jane needs to finish his trick. Otherwise, we can safely assume Patrick would have told Lisbon all 7 names on the list. Jane does his finish his trick though. And off-camera he tells Lisbon the rest of the names. I mean, why wouldn't he? It would be completely retarded to think he says 1 name randomly, then stops and Lisbon is satisfied and stops pestering him.

Then the woman who stole the baby arrives in the dead of night. What took her so long? RJ was making the video with Lorelei, AS Jane and Lisbon were waiting in the house. That's right, Lorelei Martins is still alive. So how did Red John get the names? He heard them at the same time as Teresa, as Lisbon was bugged.

Proof: On Sunday, you'll see Lorelei alive and well in Great Red Dragon. Lisbon stupidly confides information in her thinking she's reformed, but it turns out that Lorelei is still a devoted Red John follower.

Spoiler: Brett Partridge is Red John - no I'm not explaining it

I've been on the Gale Bertram bandwagon for quite a while.  In the first episode of season 3, he referred to the "Media" as an excellent tool (makes sense that Red John would consider individuals as 'tools').  His position in the CBI, along with the fact that he was sitting with Patrick Jane in the Mall in the season 3 finale (Heller showed us Red John with Jane, but Bertram convinced Carter to impersonate him).  There are so many things that Bertram says like...."I want to be there when you catch Red John" or the fact that he has been with the CBI, and under Jane's nose this entire time (keep your friends close, but your enemies closer). Jane also got a weird feeling the first time that he met Bertram.  Something that he couldn't place.  There are other clues, but I shall get to the point.

I want Bertram to be Red John.  It makes sense.  I've been so obsessed with this show that I had a dream he was Red John.  But I have a feeling that I will be disappointed because it will be Partridge.

Heller said there was a clue in the first episode of season six.  All I saw was a 666.  This has probably been posted before, but that refers to the Antichrist.  If that is the clue, then what does it mean?

Revelation 13:1-4 states (ESV)" And I saw a beast rising out of the sea, with ten horns and seven heads, with ten diadems on its horns and blasphemous names on its heads. And the beast that I saw was like a leopard; its feet were like a bear’s, and its mouth was like a lion’s mouth. And to it the dragon gave his power and his throne and great authority. One of its heads seemed to have a mortal wound, but its mortal wound was healed, and the whole earth marveled as they followed the beast. And they worshiped the dragon, for he had given his authority to the beast, and they worshiped the beast, saying, “Who is like the beast, and who can fight against it?”" 

Without doing full-blown exegesis, let me make a few remarks.  Previously, the dragon was described as having "seven heads and ten horns and seven crowns on his heads" (Rev. 12:3; the next episode title is the Great Red Dragon).  This chapter refers to the Beast (who has more crowns than the dragon) which symbolizes the Antichrist, someone who would be able to draw the whole world to himself (or in Red John's case, followers).  People will be in awe of him, and worship him, much like others do Red John's bidding without a second glance.  The antichrist will be a powerful figure, much like Red John is.  However, the point is that he will suffer a fatal wound, but he shall be healed (13:3).

This makes me think that Partridge will come back to life.  He's been around since season one so it makes since.  But I don't like his character I'm not convinced that he has the ability and charisma that Red John needs to attract followers.

So it's probably Partridge, unless someone dies in the house fire and later comes back to life in the eighth episode (Red John).  But I still want it to be Bertram.

The one thing in common with most mentalist fans is, between the beginning of our journey from season one, to the far ends of this final chapter, we have almost all suspected Brett Partridge as Red John. During our long journey, some passengers jumped off the Partridge train, while new passengers jumped on.

One thing is for certain though. Patrick knows Brett Partridge is Red John. I can't explain it. I just know. "Because when it's Red John, I can feel it."- Patrick Jane

So, as we reach the final station in the park, I say this is the what the best part of being a Partridge fan is: Its brought me closer to Jane, and helped me fathom the way he's made his ingenious plans and tricks. I truly feel like I am taking the final steps on this path with Patrick.

For those who are lost in a sea of suspects, be ready for this resurrection, as this beast emerges from the sea. Before the deed is done, you'll be taking a bullet train to our station. And for a few moments, again, we will be united in the common truth that Brett Partridge was Red John.

Ok, so Lorelei Martins appears in next episode, alive. Lisbon foolishly thinks she's against Red John, when in fact she's still his accomplice. 

And in episode 8, it's revealed Brett Partridge is revealed as Red John.

Spoiler Alert.

This sounds farfetched, but come the next episode, you'll be annoyed that I spoiled it for you.

I still belive it to be Brett Partridge. Mainly because of my theory that he shows up on two and only two fake Red John murder scenes in the show, like he was trying to figure out who was copying him in which, kills the two school students who tied up Jane. I cant say how he would still be alive, but who else could have swiped Lisbon from behind?

FELLOW THEORISTS,

Y U NO USE PROPER SPACING, PUNCTUATION, AND COMPLETE SENTENCES?!?!

Seriously, half this shit is so hard to read/follow. If english isn't your primary language you are excused.