I don't think Pj is Rj, he's just one of the popular choices so I'll be putting this here.
I just want to point out some things that might be happening in the trailer.
*LINK IF YOU HAVENT SEEN IT: http://www.youtube.com/watch?v=ExwMYqY0Uo0*
~ If you go at 0:08, you see a bald man with dark skin. That clearly is the FBI man who came and shutdown the CBI at the end of Ep.07. I believe Jane had caught Bertram (Who I don't think is Rj btw), and the man came to his rescue. Bertram flee'd the scene, and this man was probably talking to Pj saying stuff like "I got you" and stupid stuff bad guys say before they are going to "KILL" someone. You see that his team pop out of cars, probably meaning they go and save him from the man.
~ The part right after it says "Hunted", is probably after his team has killed/taken the FBI man, and Jane starts chasing after Bertram (Or maybe someone else, McAllister possibly?). When he smashes through the house I think whoever the person is slows down, and Jane gets them (Figures out they are not Rj, but they might still die).
~ Should be obvious the part at the church was the reason we saw that odd look on Pj's face at the end of the episode, he has that face when there is a presence of Rj, or an Rj face on the wall. I believe that man is 100% not Rj, but probably someone from the Blake Organization (Yes, I do think they are connected).
~ The very end is after Pj shoots him (he doesn't die ofcourse), and he is asking for Mercy. This should be pretty obvious considering Pj says "Now you want mercy"
Who I think Red John is? I don't know really. I also have a theory about how LaRoche is connected to the Blake Organization, after he cut out the dude's tongue. My best guess is maybe Bob Kirkland/Michael Kirkland (1 of them certainly died, but it could've been either) or Jane's father (I would honestly love to hear the backstory to this),