I don't think I'd like it at all if Jayne is RJ, but the signature symbol RJ always draws looks like Jayne. The smug smile, outward slanting eyes...it's Jayne's face on that wall. Nobody else looks like that.

And the Alice episode did seem like a broad hint that Jayne is the man he's hunting. The wife's absence, the daughter telling him he had to let go....it's also starting to be a little unbelievable that Jayne hasn't caught RJ by now.

RJ's abilities are suspiciously like Jayne's own. Hypnosis, sleight of hand, etc....from the giggling dying guy season 1 I'm pretty sure RJ is someone who works for the police, and is trusted by Jeyne. The remark that Jeyne has shaken his hand, is a bit of hope that it's not Jeyne.