I can't really see how Patrick Jane can be Red John, except if they somehow concoct an incredibly lame and involved and complex multiple-personality or twin-brother theory to explain away all the inconsistencies.

However, one thing that Jane said to Lisbon when she was after Tommy Volker (I think it was in "Little Red Corvette") leaped out at me.  He said of her approach "It's cold, I like it!"  And I read that Bruno Heller says that Red John "likes the cold".

Just something else to think about!