I truly believe that Bret Stiles is our man. To me he is the only actor who can really pull it off, and the only one of the suspects who is capable of having that much power and influence over such a vast number of people...just like he does in visualize. He is charming, witty and surely has a dark side. Red John uses peoples weaknesses to get his victims to trust him and depend on him....When Bret was in Jail he tried to get to Grace in much the same way.
Now looking at the facts. When Bret helped Jane break Lorelai out of jail "homeland security"(Kirkland)  on it in no time. I truly believe that Bret was using Jane as a pawn to get Lorelai where he wanted her to kill her off.