There are some crazy theories here. I will explain why i don't think its one of the names in the list, i know what Heller said. I don't want to believe that. That is the magic of 'The Mentalist'. Its unexpected.
Also the list has some stupid names which would be a real letdown if one of them was RJ. Lets go over the names :
Out of 7 :
1. Bertrum - Already proven in the final episode of season 3 or 4 that its not him. Its highly unlikely he hired that girl and O' Laughlin.
2. Patridge - NO. Only shown in 3 episodes and why would he tell Jane that its not RJ when it is RJ since RJ is doing this all for Jane. Also too obvious and too much evidence towards him which is out of the nature of the series to go with the one that the evidence is pointing.
3. Sheriff i dont know his name - Saw him only once in season 1. That proves all . If an unknown character is RJ, then the series is retarded.
4. Bret Stilles - Too obvious i think but its plausible since he owns visualize and basically can persuade a lot of people about crazy stuff, maybe the people working for him were manipulated which he is good at that. But again too obvious.
5. Ray Haffner - Not really that manipulative. Why would he leave the CBI if he was RJ. Fine ok lets say his RJ. Supposedly He left because he didn't have to be a mole anymore since he stopped killing for some time anyway and Jane had given up. Then why propose Lisbon to follow him in that job thing. Doesnt make sense at all. Could be an accomplice but unlikely.
6. Bob Kirkland - Really obvious. Maybe an accomplice or some people say an enemy but why if he was an enemy of RJ kill that guy who was at the hospital who knew who RJ was.
7. Dr. Forgot his name :D - Not him. Hardly seen him and again it would be a letdown.
Finally maybe more story is going to be revealed for each character in season 6 i think. That would be the real time to start guessing and investigating. Most people here are throwing long shots like me. Its too early.