6.5  Has no one else realized that the investigator never, never said that Visualize was her client! Cho said it, she only agreed to get the handcuffs off. It's called leading the witness and Perry Mason would have objected.
Haffner is my vote because RJ is playing a game-- who is smarter. Only PJ has been up to the challenge. Twice RH spoke of who is smarter. Playing lesser to Stiles puts him in a position of quiet power. He may or may not actually care for Lisbon, but she is important to Jane which makes her an interesting chess piece.
I applaud the producers for the tiny clues such as doves, etc. Makes for a complicated and interesting psychology of entertainment. Thx

I'm following this process of elimination...

1) Brett Stiles - Can't be him.  He would have been recognized at the Ellison Farms.  He doesn't fit the some young kid moniker used during the Ellison Farms episode.
2) Bob Kirkland - He is hunting RJ.  He is also dead now.
3) Bertram - The conversation with Reede Smith gave the impression that Reed is over Betram.  If he was Red John Reede would never speak to him like that.  I do feel he is part of Tiger Tiger though.

4) Thomas McAlister - I feel he is too old to meet the young kid reference made for the Ellison Farms - Couldn't find a reference to his age so perhaps I'm wrong.

Improbables:

5) Brett Partridge - He's dead.. Although I do wonder if he didn't fake his death to throw PJ off.  He is really my #2 choice.  I feel his voice fits RJ's voice much better than anyone elses.

That leaves Reede Smith and Ray Haffner.

I think Reede Smith is just a member of Tiger Tiger.

I'm going with Haffner as RJ.  He is a member of visualize.  He wouldn't answer the question about if he was at the Ellison Farms.  He was involved with the case where the PI got killed.. There was a reference made to he had other business to attend to that night.  He likes TL which is perhaps why he didn't kill her and just painted a face on her.  He has easy access to CBI, contacts, etc to keep up to date on the teams progress, etc.

6x5... when cho asks the private investigator, who was the client, she says he is visualise, Jane figures, that the man who hired her was RJ... soo if we put those 2 things together, RJ is from visualise, he COULD be Haffner or Styles, but i doubt, i think he is some one else for who we dont know is in visualise :)

just a thought. cant wait for tommorrow, have a nice day.

Hello. You guys are over thinking it..It's actually, very simple, ONLY Ray Haffner calls Lisbon by her first name ''Teresa''. When RJ kidnaped Lisbon, and answered Jane's call, he said: I'm sorry Patrick, TERESA can't come to the phone right now.
I'm 100% sure that Ray Haffner is Red John. =)

Throughout the show, Ray Haffner has always been portrayed to have something for Lisbon, maybe that explains why Red John didn't kill Lisbon when she found the deceased Brett Partridge

Lorelei wondered why Jane and Red John didn't become lifelong friends the moment they shook hands. This implies the first time Jane met Red John, they shook hands. Moreover, I believe the scene where Red John and Jane shook hands is of great importance, so important that it had to be included in the show. So possible off-screen handshakes are ruled out. It's the type of scene fans would like to go back and watch after Red John's identity is revealed. Luckily, the show includes the scenes where Jane first met every single one of the five remaining suspects.
 
He first met Stiles while he was recording a promotional video for the cult in Visualize HQ(Red All Over). No handshake here.
First met McAllister on a crime scene in Napa County(Red Hair and Silver Tape). No handshake.
First met Smith after investigating a crime scene(The Crimson Ticket). The CBI team is about to leave when Smith and his colleague arrive and end up fighting with Cho and Rigsby. No handshake here either.
He first met Bertram on a crime scene(Red Sky At Night). They shook hands.
First met Haffner after Lisbon's team was suspended in the beginning of the fourth season(Little Red Book). They shook hands.

So it's just Bertram and Haffner. Of course all this is based on the minimum competency expected from the producer, which has been questioned several times. Personally, after Red John's identity is revealed, I would like to go back and watch where he first met Jane. The handshake was a turning point, it has to be included in the show. Jane's emphasis on the handshake part and not just "meeting" would support my theory. The problem I face is similar to what Rosalind's description theories and Red John's age theories face; namely, why didn't Jane take them into account. Using Rosalind's description he can easily rule out Bertram. And knowing that Red John was a younger than 30 in 1988 would rule out Stiles. But Jane didn't do it, at least it looks like he didn't. It's possible he's trying to trick Red John into believing he's so far from catching him while he's actually closer than he anticipated. It's also possible the show is not flawless, but I highly doubt it, at least not on the scale of ignoring all of these data, but it's still a possibility.

The Mentalist - Episode 6.08 - Red John - Press Release

Taken from: SpoilerTV http://www.spoilertv.com/2013/10/the-mentalist-episode-608-red-john.html#ixzz2jLa1jOdA 

“Red John” — Patrick Jane finally comes face-to-face with Red John, the serial killer he’s tracked since the madman murdered his wife and daughter. For 10 years, Jane has doggedly hunted his nemesis in his search for justice, on THE MENTALIST, Sunday, Nov. 17 (10:00–11:00 PM, ET/PT) on the CBS Television Network.
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I'm gonna die this episode.....