Season 1*16 at 39:45 ....

He appears driving a car that looks a lottttttttt like RJ's car. Plus he came out of nowhere like he was waiting in his car in the parking place. He sees Dan holding a gun and looks at him in a strange way and just continue driving. Maybe he told Lisbon to come and help the blind Jane and Van Pelt. Idnk.


Plus from reading a spoiler that was posted here a few hours ago :

 "He desperately wants a relationship with jane to the point where he exposes himself and puts himself in jeopardy" (Simon about Red John)"…Baker, known for his wit, charm and heartthrob puss, is an actor of considerable depth and passion. And the moment of death itself with Jane straddling Red John, and looking directly into the eyes of his prey is one of shocking intimacy." Simon Baker: "It’s almost like a love scene, as perverse as that sounds. ….There is no human act more intimate—not even sex—than killing another human being and watching him die." Whoa."    Well when I read it I only thought of Ron coz I sense in his looks to Jane and Lisbon some of that..Like he wants to be close to them. Maybe that's why he didn't hurt Lisbon (if he was RJ I mean) coz he felt the bond between Jane and Lisbon and secretly wants some of that.
 

and in season 2*08 when Rebbeca was poisoned and Some of RJ's body appeared (his back side and some of his hair) his figure wasn't much like Partridge (who's my num 1 guess) who's a little bit skinny, but it's much like Ron's figure plus the hair color was close too.
Plus Ron moves a lot without getting people's attention a lot. That's why no one noticed him maybe.  

Well I hope that wasn't too long.
Thanx for reading!
I can't wait to know. :)