My theory will probably not be among the most popular theories here but here is how I see the things.
We all are aware that only people from the list of 7 were able to be on the right places in the right time for killings that Red John committed.
We are also aware that Heller already stated that "we can trust the list," but also that we would be disappointed when we find out who Red John is. We also heard that after some time in season 6, it will no longer be about who Red John is, but about catching him.
Therefore, I can state my theory here:

Red John doesn't exist as a single person. There might be a leader of the Tiger,tiger organization, but that's all what his job is. All of the Tiger, tiger members are actually Red Johns for themselves. The organization kills everyone who comes in their way somehow, and acts under the alias of Red John. It's simple, they have many regions covered, they act together, and share their assignments.

Sheriff Thomas McAllister is, for example, Red John for Napa county, Gale Bertram's job is to keep Patrick Jane in his sight, and under his control. We've seen Reede Smith in action in the last episode. Brett Partridge's job was removing the existence of  eventual evidence that was left on crime scene. Bret Stiles' job... probably the biggest one, he's most probably the brain behind this whole organization. Ray Haffner... well, you can call him Roy Tagliaferro if you preffer.
The thing is that the list is probably too small for everyone that is involved.

Also, remember the "He is man" clue from Mexico, in an opening season. Thinking about it now, "he is many" would fit perfectly.

I've kept it short and brief, so I probably left some things unexplained.

Red John is not left-handed. A left-handed person would not paint with his right hand as Red John did on Lisbon's face.

By the way, where did all the blood on Red John's knife come from? Partridge was already dead and his blood almost dried, so the blood on Red John's knife should also have been dried or dropped off while he was waiting for Lisbon to find Partridge. Did he then stuff his knife in Partridge again to get some blood for his painting? Could he not just put his fingers into Patridge's wounds to pick up blood? And how the heck did he call, talk and hang up the phone while his both hands where busy? Since no reasonable explanations yet has been given about all this, perhaps it's just another blunder by the writers!

This is for the people who claim that high profile guys like "Stiles or Bertram" could not take sessions from Dr. Miller under fake names because they would be recognized. 

Another angle here: High profile people can easily make an agreement with such a doctor on keeping their name secret in records by generating a fake name. After all, these sessions are made for the individual who's taking them and not for public use (unless the law enforcement officials demand the info with required permissions by the court). A doctor wouldn't miss the chance to heal a patient with such high profile even though she has to keep his name a secret. Her benefit would be direct or indirect recommendations. Think about it...

I think Micheal Kirkland has a backup plan in case of his demise. I think they involve helping Patrick Jane "finish this thing". They fore shadow this by showing the multiply cups of coffee. He is prepared for any eventuality.

Once he realized he was duped by Patrick Jane with the fake list then he felt that he might not be the right man to take down Red John. He decides to initiate a series of events to help give Jane a clue. Kirkland was smart but not as smart as Jane but maybe he knew how to help.

I think the next couple episode descriptions could fit with this.

6x05 - The Red Tattoo - When a prominent member of Visualize is mysteriously killed, Jane
investigates in the hopes that the case will provide a clue that will
lead him to Red John.


6x06 - Fire and Brimstone - With the final clue in hand, Jane attempts to gather the remaining red john suspects in one place in hopes of finally revealing his identity.

I think the events in 6x05 were initiated in some way by Kirkland to give Jane the final clue.

This isn't really a theory just some speculation.

I think it is Burtram personally. Haffner is the red herring. Burtram has a temper and a bad side. Red John is manifested through his anger and rage.

Anyone else think Dr Roy Carmen, the CBI psychologist from way back has some significance?

Just look at the name alone. ROY CARMEN. He is a psychologist, and he counselled both Jane and Lisbon after the shooting in 2009. Think he was in two episodes only?

But the name......

Carmen Lee

Roy Tagliaferro

Could be why 'Jane' reacts like he does when he hears the name Carmen Lee.....

He thinks, psychologist. He thinks Dr Roy Carmen - blast from the past, way back to the beginning almost 2009.

Could be a red herring and simply an interesting co-incidence, but maybe not.

LISBON'S FATHER.

Yestarday i thought michael kirkland waals red jonh. But thinking about bruno heller's clue at the final of 6x01..... the clue might be... lisbon was not killed why??? Because is his father.
Pj wants to kill Rj. Lisbon always says Rj is going to prison. Guionists need a good reason for Pj dont kill Rj. Maybe is this... teresa will claim Pj not kill his father and patrick as redemtion will not. Rj is going to jail. Its not probably Rj become muerdered by Pj.

BTW, didn't Bruno Heller say that 6x04 would reveal why Partridge had to die in 6x01? So where was that explanation? Please help me out here, because if the answer was there, I certainly missed it.