In my opinion Virgil Minelli is red John. I've rewatched most of the scenes with him in and the looks he gives Jane and the subtle hints he drops. He also has short hair, around or under 6ft, the only doubt I have is his voice unless he uses a voice modifier. He also employed Jane.

I have a feeling rosalind harker is more involved than she lets on also.

I think it is Jack Coleman from S03E04, the guy whom gifts Patrick a gun. He basically got away with murder and tells Jane it was worth it. Little bits of dialogue stick out in particular, like how he says "Anger is unproductive, and unhelpful." To which Jane replies "Well I don't know, some people it's invigorating." Only to receive a maniacal grin afterwards. He also says"You want to know my secret for inner peace? It's called reconciliation..." to which he goes on, almost as if to coach or comfort, that he needs a new start to which he decides how he lives thereafter. Throughout every conversation, Jack Coleman seems to trot carefully and plan ahead, just like RJ. He even "reads" Jane at one point.  Lorelei says both he and RJ are similar, and the similarities are quite peculiar.

Flaws:
-Denies tea
-Doesn't shake hands
*Has son

Support:
-Matches RJ Profile (Smart, 30yrs.+, killer, much like PJ)
-Odd use of dialogue and interaction
-Gives Jane a gift (He has given "gifts" to Jane before)
-Financially well off
-Has high friend who tells him that some one from D.A.'s office helped his case.

Additional Thoughts:
Despite denying tea, we know that he is a patient man, one that waited and planned for 10 years just to kill. And denying tea one time doesn't mean he doesn't drink it. TV shows don't always have to reveal scenes, they are often added later. This could account for the two flaws. *And as for his son*, RJ is complex and intricate, he knows how to work people and work around people. His actions either make a point or lead to a reason unknown. So really, it doesn't matter who he is affiliated with in his personal life, only the RJ life affiliates matter. Giving the gun to PJ could foreshadow how RJ's death will happen? But I have digressed.

P.S.
Uncertain if it matters, or if others have noticed it, but what do you guys make of the tiger painting on the wall in Bradley Whitford's (fake RJ) house? It may or may not have a sub-direct correlation with the plot.

I think if there is any chance Red John turns out to be a woman it has to be Kristina Frye.I didn't think too much of her at first but in the season 2 finale I was really suspicious of her with a lot of things not adding up like at the beginning when she claimed to have read the waiters mind when she said roll tide and later Red John said the same and we now know that Red John is someone Jane knows and he would have recognised RJ at the restaurant but he didn't recognise anyone because there was no on there to recognise just Kristina.

Also in that episode Kristina went on TV about RJ.I can't think of any one that would do that unless they know they won't be killed by RJ which surely means she is RJ or knows him well enough so he won't hurt her which he doesn't because he kills the woman asking the questions.

Kristina is also a tea drinker like Red John and we know she definitely shows an interest in Jane like RJ would and there isn't a better way to get close to Jane as going on a date with him.Kristina also believes she is a psychic and thats how she knows that Jane's wife had her toe nails painted in her own blood so if she isn't psychic she is Red John and Jane doesn't think she is psychic but just good at guess work like Jane so both ways she still could be Red John.


If she isn't Red John she had to be involved somehow.