I'm betting on Raymond Haffner. This is my theory:

Let's begin from Sophie Miller's description for Jay Roth (a.k.a. Red John or Ray Tagliaferro). I should pay attention just on the remarks we can surely proove in the first to episodes of the new season:

- the whistle - in the second episode are 3 people who are whistling (hope I wrote correct) in some circumstantions: first one is Ray Haffner, the second one is Reed Smith and the last one is Thomas McAllister. Ray and Reed have a short whistle, while, in the end of the episode, Tom has one longer. We would be tempted to say that Tom fit best the description. I don't think so! I'm guessing on one with a medium whistle ---> Raymond Haffner!

- damaged and narcissistic personality - There I woul think about Gale Bertram and Raymond Haffner (yes! again him!). I also woud thing about Brest Stiles (but not too much). The free are, now, when I am writting to you, leaders, in some way, of their groups: Gale Bertram CBI director, Bret Stiles the Visualize leader and Ray Haffner  a NEW leader of a private investigation group (or somehow). What intrigues me is why, in the 5th season, Haff decide to create that private society. I've deduced that he maybe likes to controll the situation, being in the center of the group without being seen or known by anyelse. He cares his body, him entire. That could be a narcisistic type. His face on the final of second chapter really scared me. Is something to care about. I don't know very well, but when he drinks coffee with Lisbon on that CBI rooftop, I bet he stay with his back to the view... About the damaged ehing, I can't say anithing.
- looking convincingly - yes, in my opinion Ray Haff looks so. 

Ray Haffner looks like he cares about Lisbon, maybe even loves her. He've made her that offert for a private job as detective: to no body else but her!
Now, I hope you noticed how (in the first chapter of season 6) Red John moves his finger(s) on Lisbon's mouth. You would say that he is doing so because he paints her face (mouth). But look on the way he is doing this: very gently, like he cares about Lisbon. He wants the paint to be accurate, even perfect. That scene prooved me that Lisbon may signify something special to him. (R.J.) !
Back to Haffner! Look the way he seats on the Lisbon's bad, at the hospital. Even Jane wouldn't stay like this (not for the first moment he enters the room!). I would appreciate the Haffner's seating is just like a boyfriend who would do this for his girlfriend! ---> Ray Haffner likes her, R.J., may likes her... Or is just a way to proof each one domination towards Lisbon. Just a guess...

So that's why I'm thinking that Haff could be Red John!