Im going to be laughing my arse off if Red John is the supposed victim in the blast who faked his death.
Talk about rubbing salt on the undead patridge wounds, in the extended preview we can see that McAllister is up on the board with stiles and haffner.

Im guessing that McAllister supposedly died in the explosion(im guessing theres a body which is burnt up in a sheriff uniform) and so joins the ranks of Stiles and Haffner(i dont think either of them died in the explosion though) as non
Red John candidates.
The most obvious choice now is Bertram and it will most likely be him but i have this niggling feeling in the back of my mind that there will be one last twist.

It could just be that Reed Smith is Red John but I remember reading how Robin Tunney was surprised at Red Johns reveal and she has stated before that she was suprised that Xander(Mcallister) was a red john suspect and that she expected Michael Gaston(Bertram) to be a red john suspect. (This is me just paraphrasing what she said, though in saying this im fully aware that Reed Smith would deffinately still be a surprise and probably a bigger one infact)

http://www.youtube.com/watch?v=gEXVZcADxC8
If you notice at the end of the 6.07 extended promo, they are showing a house with a tree in the front. I cant remember exactly the words but didn't patrick say that Red John lived alone/with his mom in a house with a lemon tree. Im too lazy to look up the exact quote but it was in the first episode when he appeared on a tv show and belittled Red John. (Just a note, Michael Gaston(Bertram) tweeted a picture of this set awhile back meaning he was at the location of this scene...)