I think Red John is one between:
1) Director Gale Bertram
2) Officer Ron (CBI Ron)
3) ADA Osvaldo "Oscar" Ardiles
4) Alex Jane, PJ's father
5) Officer Brett Partridge, CSI
6) Dr. Linus Wagner, psychiatrist, fake RJ
7) Walter Mashburn, billionaire
But I write the most possible theory, Bertram.

I find a proof against Bertram.
There are, maybe, very important. A link between Timothy Carter, the fake Red John ,and the Director.
First of all, I say that Carter could not have learned from O'Laughlin of the trap, would not have suffered tempoi, then has two RJ moles or he himself is the CBI, and has consulted with the mole and he understood everything. The killer at the motel only served to confuse and deceive Jane.
But, while Bertram is drinking tea when Lisbon is talking to him, reading a newspaper.
The next day at the mall, the same newspaper is in the hands of Carter (perhaps contains information on the family of Jane), after Bertram is go away.
Here are the photos:
http://i48.tinypic.com/4qob2u.jpg

http://i45.tinypic.com/msyc6c.jpg