Not a theory, but still interesting. There's this Mentalist fanatic on Youtube; his name is Americ and he's part of a channel called HappyCool. He makes wonderful weekly reviews of The Mentalist, and he occasionally gets the privilege to see episodes prior to airtime. 

This is Americ's reaction to the Red John (Season 6 Episode 8) episode. There are no spoilers, only Americ's reactions coupled with some soothing music.

Definitely worth the watch, and if you can let me know what Americ reacts to at 1:38, I would love to know. Is it an RJ reveal, or is it a Jane-Lisbon moment?

Link: http://www.youtube.com/watch?v=vWYpReqi678&feature=c4-overview&list=UUamPGTREfS0YRJBkC7cBHPg 

Enjoy and continue theorizing. I love them.