I don't think Bret Stiles is the only Red John, but he is totally the brains behind the operation. My guess since the 2nd time the team went to Visualize (i cant remember the episode), I guessed it was a team effort.

I think Bret Stiles could easily be Red John, because he has that charming personality, and he also has the brains to do it. He leads Visualize, and I think that some of the people on the list of 7 (excluding McAllister, Smith, and Bertram) have been a part/are a part of visualize. We know that whoever Rj is, was a part of Visualize because of the Red Farm episode. Bret in my opinion doesn't do any of the killing (maybe the first few, but thats about it). I think that all the people involved with Rj have been a part of Visualize, because if they weren't then why introduce it anyway?

My theory is that Bret convinces the people to do the murders, its as simple as that. In S06EP02, the scene about Lisbon's Dream is useless, and that it's just another way Heller is trying to throw us off (like in S3 finale when Jane killed who he thought was Rj, but wasnt). I do think that Grace is also part of this team, but not from the beginning. In the EP03 promo, she gets married to Rigsby (the dude doesn't really look like him), this is something that will come in handy later on. I think she joined sometime before the S4 finale, where she killed Craig. I think that Craig was killed for Rj's sake. The thing that always gets me is that she has RED hair, and they are trying to catch RED John.

I think that in the Season Finale, things are going to get crazy. Rumors are that Rj is revealed on EP08, titled the "The Great Red Dragon" i believe. I think that the rest of the season will have really important people killed, some names I think of are J.J. LaRoche, atleast 4 other people on the list, one member of the team (most likely Rigsby/Grace), and also whoever Rj is.

Something I hope to happen in the finale is that Jane isnt the one to catch Rj, they lead this all up to think that Jane is the one that solves EVERYTHING, I think that Lisbon will be the one who gets Rj.

This is about Bret Stiles, but I'm actually not accusing him, I'm exonerating him. And what I'm about to say may sound farcical, but I'm serious. This is my first time submitting a theory here, and I hope this does not go against me as a theorist for not being substantial. But... 

Bret Styles cannot be Red John, because the visualize symbol is a variation on the CBS logo -- Network that airs The Mentalist. I'm quite serious about this. Although I don't want to stretch my theory too thin and speculate about the significance of the similar designs, I think the similarity is intentional, not coincidental. 

Before I submit another theory or theories accusing other people, I want to say that Bret Stiles is the most fitting suspect for several reasons that have already been mentioned by others in this forum, and the fact that he is the most fitting subject DOES NOT make him a red herring. But I still don't think it is him. 

I do, however, think visualize has some involvement or influence in the turns of events concerning RJ, because, for instance, Stiles has too much knowledge about things Red John, he's too powerful, and there are too many connections like the murders committed in the basement of that house years before RJ's murders became public. For that matter, Haffner, a member of Visualize is dirty, for certain -- but not necessarily RJ or one of his disciples. 

The list of 7 could very well involve people who are all in this together somehow, including RJ whom I believe is an individual, not a team. We know that Bertram and Kirkland have had private conversations regarding Jane and Red John; we also know of the trio in Bertram's office in episode 6.2. I think there is another trio that will be revealed very shortly: Stiles, Haffner, and Partridge. We will learn about the connections in the fourth episode this season. Note, that this consideration on groupings involves all 7 in one way or another, although the trio I suggest has yet to be materialized.

Some of the people on this list are blood relatives, or else one of them has a brother who has been affected by the RJ killings. I say this because there is a sibling issue with RJ's MO. On more than one occasion we know of a girl or woman whom he killed or had killed whose sister was spared. The basis for my suggesting there is an important  fraternal relationship in the Red John ring is based on this motif and on another relevant motif "Tyger Tyger." 

There are also two Brets -- but not really. One is a Bret the other is Brett. Brett Partridge is one of the Tygers; Brett Styles is not -- IMO. But if we wanted to get involved in anagrams and alliteration and what not, there's lots to play with with the T's in these names. Then again, these sound games are insubstantial -- maybe... maybe not. Show titles often indicate significant, clueful plays on words, and most of RJ's alias's are plays on the pseudonym "Red John." so it's not out of the question for Heller and other writers to use these devices. 

After watching all the episodes involving red john i came up with the conclusion that he can't be someone else than Bret Stiles, or at least Stiles is the mastermind behind Red John. Red John would never accept to be emberassed in public, especially by jane, as it happend with McAlister, Haffner, Smith or bertram. So the only one left, beside Stiles,  is Kirkland but he is just a missleading character introduced by the producers. Only bret has the capacity to play such a game with patrick, all the other would have been lost that game long time ago.

In Red All Over, when Patrick introduces Lisbon to the little girl, he says "Theresa" the same way Red John says it at the end of S6E1. A previous poster had asked about this, but I can't find the post now.

Basically everyone who appeared in Lisbon's dream (assuming people are up-to-date)
are relative to the core plot within the Red John story arc, at this stage it's pretty clear those men are all a part of the so called 'network' of Red John's people.
The show has sited Jung and reveals truth in dreams. 
This dream however deliberately avoids including Brent Stiles.
Clearly the man is one of the only ones capable of influencing peoples minds n hearts, 
to flip the logic on it's head and make the cult like Red John image work.
He is a tremendous actor therefore worthy of the role of Red John. 
He was very clever in getting into Van Plet's head very quickly, he's rich powerful and really the only one who could match Jane. The others are minions and have taken on important roles in the whole operation. Jane cashed in an important favor from him at one time also that lead to the assumption that despite his virtue as a cult leader he remains in touch with the underground parts. 
He will be able to give the script a good read play the part well, vex minds and be hidden the longest. If anything, I would see this as a safe and logical step in the already 6 season arc, I mean come on!  

Before Bret Stiles hair greyed with age he had a full head of ginger hair! Let me reiterate that for the sake of clarity, Bret Stiles IS A GINGER IN DISGUISE! Therefore he has NO SOUL but NO-ONE KNOWS! Case officially closed.

We don't know what happens to Patrick's father
I have a theory: I think he's Bret Stiles (his past is doubtful), and Red John!
This is his father who taught him Mentalism!
My justification:
"In the mid-1980s, when Patrick Jane was 16, he worked in a carnival as a psychic boy wonder, with his father Alex who MC-d the sideshow. Patrick had what his father called "x-RAY eyes," his amazing skills of observation, deduction and induction. He had a rough existence with his father, the only adult in his life, whose treatment and use of him was tantamount to child abuse. When Patrick refused to scam a dying girl and her grandmother, his father threatened him and forced him to do it. Jane later said that he never went to a high school, presumably due to the nomadic carny life. " 
http://thementalist.wikia.com/wiki/Patrick_Jane