http://insidetv.ew.com/2013/05/06/mentalist-finale-season-6-red-john-list/
I invite you all to check out this article of a convo with Bruno Heller. I guess he could be LYING to us, but I'd like to think he's not.

According to Heller:

Red John IS one of the seven people on the list.

Red John is NOT Jane.

Roselind Harker (the blind young woman who knows Roy Tagliaferro AKA Red John) has described him as being of average height (just under 6') with short, straight hair. He is neither strong nor weak in muscular build. He also has rough, calloused hands.

Combine that with a deleted scene in Season 1 (if that can be trusted) where Jane tells the others that RJ probably has brown hair and perhaps blue eyes and it narrows down the list by quite a bit.

Seems to me the only one's left are Robert Kirkland and Brett Partridge.
Both are around Jane's height of about 5' 11" (just under 6'). Both lean in build with short brown hair.
Kirkland is almost too obvious. They are really pushing his whole bad guy persona a little much this past season. Plus, in another earlier interview with Bruno Heller, he mentioned that RJ has been a sort of Where's Waldo in scenes all the way from the very first season. Kirkland is relatively new.

If Jane is to be believed, the only one with blue eyes and every other aspect would be Partridge from what I can see. He seems obsessed with the Red John cases. Killers love to put themselves right in the middle of their own investigations- being in forensics would certainly help that. He bugs Jane - another win for RJ there. Plus - he's just downright creepy.

Honestly, I'm kinda disappointed that Jane's father isn't on the list. I know, he's probably too old to be RJ and he hasn't been shown shaking Jane's hand in any episode ( if he even would), but THAT would make for interesting TV drama. Plus, he'd be more apt to know all of Jane's thoughts and actions.

But, in lieu of this new information. I'll have to go with Brett.