Bret Stiles, Gale Bertram, Ray Haffner, Reede Smith, Robert Kirkland, Sheriff Thomas McAllister, Brett  Partridge - One of them IS RJ. Its been confirmed by the creator and others. 

Red John most likely has some kind of link to Visulize and is also well funded, he can pay for Limos, buying property and even a new life for Jane.

Smith and McAllister have not been in the series enough times to be the main bad guy, also Smith is fat, RJ isn't from what we've seen. If one of them was RJ it would be extremely disappointing. 

Kirkland shook hands with Jane an episode before Lorelei told Jane they shook hands, she can't have expected them to become friends in one episode ?

Partridge and Jane do not get along, Jane insults him and calls him a ghoul and he also talks about murders that were not committed by RJ as if they were, RJ hates them. 

With them eliminated i believe that RJ is one of these 3.

Brett Stiles.
Ray Haffner.
Gale Bertram.

And out of them i pick either Haffner, he has money, proven by offering Lisbon a job that had a huge pay check and he has his own agency and is an ex agent so would have loads of contacts. 

But in a way i hope i'm wrong and when RJ is revealed its a total shock !!!


Cheers