I am totally against the idea that RJ is BP but I've found another resemblance. 

You must all know the famous words heard in the church on 6x08 promo saying "The game is over and I won". If we assume that it was Red John saying that and if we compare that voice with BP at 2:59 (* We have a schedule to keep amigo) from the link below, I can say that it's a hit.

http://www.youtube.com/watch?v=hVmQFzq8Jeo

Still, I believe that it is definitely idiotic if the guy who saved patrick from the copycat killer kids is BP and that Jane didn't recognize his voice. But still, you never know what happens, right?

1) Red John or Red John's accomplice put blood on Lisbon's mouth only after the phone conversation was over.

2) Looks like she could have been alone and able to speak freely for the end of the Season 4 finale where Red John is on the phone, too.

3) She is religious, and would likely think of herself in religious terms: hence the Tyger Tyger poem, the symmetry of good and evil (Lamb and Tyger) inside herself, inside Jane, and between the two.

4) You can spell her name with letters found in the Final 7 list, which might give the showrunners a sneaky way out of their public promises.

5) Jane goes to a church after the FBI kick him out of the Red John investigation with Bertrum on the run, and in the last scene, the camera lingers on a painting of a female religious figure (the Virgin Mary, I suppose? --> mother --> Mother Theresa) surrounded by adoring followers. Aside from Jane's face---looking rather broken, arguably---, that's the last shot of the episode.

This would give an interesting dynamic to Lisbon's disapointed look when Jane appears to give up at the end of the last episode, as well as to the initial meeting of Lorelei and Lisbon at the end of season 4.