Patrick Jane IS NOT Red John.
Proof, you say??? Okay - episode 23 from season 2 proves it quite well I believe; so Patrick is off the list for sure.

Red John, although having a sophisticated cult like following, IS 1 single individual male and not a number of people posing as te same individual. We know this due to a) the discription of the blind woman as to him being a male of average height , loving classical piano music, soft but rough hands , etc. b) his voice we hear over the radio strapped to Waynright, c) always referred to as he or him and d) this last episode "red barn" proves that he was in fact a member of visualize who worked on the farm.
The last episode also proved that Red John was or still is a member of Visualize . Which would help explain why Bret Stiles told Jane he had privlaged information on Red John & would also explain part of Red John's having a large organization & resources like Visualize.
We also know that Visualize has the 1 mole inside te CBI as revealed in Red Barn, but also Van Pelt who seemed to open up to Stiles while in custody, had the outburst while questioning the priest, where she defends Visualize, is obviously a suspected mole now as well.
Bret Stiles may not be Red John, BUT there is no doubt in my mind that Stiles knows who Red John is & still has communications with him.

Ray Haffner Now possibly a Red John suspect after "The Red Barn" episode.  He fits all the criteria so far set by the show: High ranking member of the CBI, a Visualize member (which would describe why Bret Stiles knows so much about Red John), he has shook hands with Jane, and after the evidence from "The Red Barn" it seems possible he was at the farm in 1988 when one of the first Red John smiley faces was drawn.  He fits the age, description, and mental intelligence of what we, the viewers, feel Red John is and has.

I just read an interview online with Bruno Heller about season 5 and here is his exact quote, "The trick is going to be — and this is coming — bringing the audience along and making them second guess themselves and ask, “Is that him? Is that him?” So this is why he has brought Haffner and kirkland onto the show to make us second guess ourselves. With that said, I do not think RJ is kirkland or Haffner. I'm still very curious to know how PJ knew how to go to Brett for help to get Lorelei out of prison. There still is a lot of questions that need to be answered before we can really point the finger at anyone. I have a pretty good theory, but don't feel like posting it tonight. 

Here is the link to the interview http://insidetv.ew.com/2012/05/18/mentalist-finale/