I am unsure about WHO Red John is but as much as it would be an interesting twist, Patrick Jane as the man is too unlikely. How could he have 'seen' Red John in the episode where he is saved if it is him...

I believe that Red John  will be someone tied to the story in a small way but no major role. This is in conjunction with a pattern that runs throughout every episode where every killer has a small part in the episode, and then is cunningly caught.