So, I watched S02E08 again and probably I found something. Two cops are taking Rebecca, Bosco's team's secretary, away, after Jane interrogated her. Rebecca sees another agent coming, and she smiles. She smiles because she has recognized him. He's her "true love", the only one helped her with her dark past. He's, in fact, Red John. She thinks he's here to save her, but he kills her.
The interesting thing is that we see RJ walking, and for a moment, few frames, we see his hair from behind. Unless he's wearing a wig, he has brown hair. This excludes many RJ suspects from the list.

Now, the actor who is going to be RJ never played him before, but I don't think Bruno would show us a brown-haired man when the real Red John doesn't even have hair, or it's white (Bertram and Stiles). We don't know if Haffner dyed his hair, but it's a possiblity. Furthermore, RJ in S02E08 can't be Mcallister because his hair is completely different (but we must remember the wig possibilty).
Again, it's clearly not Smith, because Smith is too fat, and we see that RJ isn't when he's walking.
Then we have Kirkland and Partridge left. Kirkland has brown hair, and we saw he's definitely dead.
We can't say the same thing of Partridge (If only Lisbon shooted him on the knee we would be sure that he's gone).

All in all, if it's not Partridge, one of the Kirklands or Haffner, they made a huge mistake.
I choose Partridge because he has always intrigued me. Feel free to comment and criticize me.

P.S. Apologies for my badEnglish