Of course Red John ist not Bertram. But it is Bertram we see approaching Jane in the church (next week's episode teaser) and he says "The game is over and I won". That's when it began to dawn on me - how would I proceed the story from here if I were a screenwriter?
Jane will shoot Bertram, even though he knows he's not Red John. Bertram was sent to die in the church by Red John.
Jane will then be approached by the "real" Red John. He will be revealed, but... Jane is unable to kill him. Because RJ has a life insurance: The life of Lisbon. He will say to Jane, that the moment he will find his revenge, he will AGAIN lose everything that is important to him: Lisbon, who would be killed by one of his acolytes immediately in return. So he says "Let's call it a truce".
Jane is forced to let Red John go - But the world will believe that Red John is dead (Bertram). It's just us (the audience) and Jane who know that this is not true.
The remainder of The Mentalist show will then be in a world where everyone thinks RJ is dead. Even Lisbon. The thrill will be: Will RJ return and start killing again? The producers could let him come back, maybe they'll decide upon how the ratings develop.
Ultimately the moral of the story is: You have to let the past go. There is no such thing as revenge. And RJ was right when he said "I'll show you clever". He know that Jane is unable to sacrifice the life of Lisbon.
Oh, and you want to know who RJ really is? No one on the list.. It doesn't really matter actually. It could be Mashburn or Bosco, somone who most of us didn't have on the radar.
