I think Bob Kirkland is Red John.

My theory is this I think he was on the carnival with Jane all those years ago, that's how he knows everything, when he and Jane first met he asked him. Do I know you? As if he recognized him. Plus Lorelei was murdered in place full of carnival things and if you remember Bob told Lisbon that his parents traveled a lot. People travel a lot on carnivals. Thoughts?

Also, Bob was there at the time Lorelei was killed. Also he killed Jason Lennon to shut him up in case he would remember and give him a peaceful death.

He said to him do you recognize me? And seemed relieved that he didn't.

Then he said to him I'm a friend and he also said lets face it Jason if you were to live you'd face life in prison so he drugged him quickly.

Think about it.

1. Rebecca -  Poisoned her - quick death.
2. Kristina Frye - Made her mind believe she was dead.
3. Jason Lennon - Drugged 
4. Lorelei Martins - Stabbed   

The following were all quick and painless just like he said it would be to Lennon. 

Now I have just watched the scene 2x22 and Red John taps him on his arm and then Bob does it 5x18.

This makes me more convinced that Bob is RJ 

Now, I'm pretty sure it's not going to be as easy as Bruno Heller made it loke in his later interview. He's making us believe that one of the names on that list is going to turn out as Red John. No twist plots.
However, I can't believe him.
First of all, many of the subjects of the list such as McAllister or Reede Smith are just ridiculous. Who wouldn't feel disappointed if, after 5 seasons, a character that has only been shown once or twice, ends up being Red John?
And I'm sure their goal is not, at least willingly, to disappoint the audience.
Some other subjects like Stiles, Bertram, Partridge or even Kirkland might be better choices. They've been dropping "subtile" clues throughout the latest seasons, just to keep us busy and thinking, believing that we're smart enough to figure out who Red John is.
In my opinion, Red John's identity will surely disappoint all of us. We've been waiting for him for too long. However, the writers like having fun and I really think that Heller has played us all by saying that the real name is "on the list".
What if that one's not THE LIST? What if Patrick is really one step ahead of him?
I find the theories about the personality disorder absolutely ridiculous. Taking that into account, I think they'll surprise us next season with another of Jane's tricks, although I'm certain that we're quite close to knowing a lot more about his real identity.   

A blind woman who had a relationship with Red John (aka Roy Tagliaferro) described him to Patrick Jane. She describes him as a man who is just under 6 feet tall, short straight hair. She said he was neither soft nor very muscular. She told Patrick that Red John did have strong, rough hands.Red John's signature is a bloody smiley face. He draws it on the wall of where he kills his victims. The smiley face is drawn with two fingers wearing a rubber glove before the blood dries. It is drawn in a clockwise motion leaving a slight opening at the top. The eyes and mouth are drawn in blood as well. Before the blood dries, it runs as if to make it look like the smiley face is crying.

Red John is nearly flawless when it comes to cleaning up evidence he may have left behind, he has short straight hair, he uses a rubber glove to draw the face, and has rough hands most probably because he uses his hands in his line of work. Red John likes people to see the crime scene in a specific order (smiley followed by body). a man who works with police officers and forensic agents would know how to position everything appropriately. He has a soft, slightly high pitched calm voice. On top of all of this evidence brett is on jane's list of 7 and has a strange fascination with red john. Also William blake (poet who made tyger tyger) also created a painting of two dead birds hung by their feet "A brace of partridge". If its not brett partridge it has to be Jane himself I can see no other characters that so perfectly fit the descriptions provided

You may think this is a bit stupid, but the real thing is that Red John nowadays is... nobody. I mean, I bet the writers haven't chosen yet who he is, so everything we can think about means nothing right now. I wish they had chosen who Red John is a couple seasons ago, so our "investigations" could make real sense.