My theory? Maybe the craziest I know but it makes perfect sense.
Here it is:
Maybe none of the 7 suspects is Red John. Let me explain myself. Lisbon and Jane don't know how RJ knew about the suspects months before Jane started to analyze who could be RJ with his thousands suspects.. Even Lisbon thought he had magic powers or was a psychic! But... RJ is way clever than that. 

Red John is a master hypnotist. We all know that. So maybe he hypnotized the 7 suspects, wether they are his disciples or not. Red John hypnotized all of them so they could give Jane some ''hints'' they [maybe] are RJ. And Jane goes with the hints instead of thinking outside the box, thinking like Red John. But soon, he'll realize it.

So let me recap it: none of the suspects are RJ. They all were hypnotized by him so they could mislead Jane into his own investigation of finding out who is Red John. I don't know who he is and I won't accuse someone. Great job RJ, but Jane will catch you... 

Even if...

...there is something bigger than that. I can feel it, do you?