I think the only theory that makes plausible sense, and also will give us the shock value we want, is that Red John is Bob Kirkland's identical twin brother.
My theory: Bob Kirkland's twin brother was first a part of the visualize cult. Which is when Bob lost track of him. He then parted ways with Bret Stiles and started his own sort of cult following as Red John. (Which would explain how Bret Stiles always seems to know things about Red John) The twin would routinely pose as his brother, and that is how he became associated with the Tyger, Tyger association. This allowed him to get away with so much, and also allowed him to stop witnesses from testifying (by having the organization kill them) and allowing him to find out inside information. The followers of Tyger, Tyger always thought they were following orders from that organization, but it was actually Red John. (which explains why so many of the suspects were a part of the organization, but have no clue who Red John is)
I think everyone on the list is asssociated with Red John, because of the organizations they are associted with. Visualize and Tyger, Tyger.
Thomas McAllister, Reede Smith, Gale Bertram, and Brett Partridge are all a part of the Tyger, Tyger organization because of their vices, not because they are Red John. Mcallister- Some sort of inappropriate activity with women. (that one epsiode when he was being creepy with Van Pelt)
Smith - Drugs, and killing the little girl.
Bertram- Possibly the leader of the organization, obviously corrupt in every way possible.
Partridge- Maybe necrophilia? haha
Then Bret Stiles, and Ray Haffner are associated because of Visualize. Red John would not be a member of Visualize he has his own cult following.
Red John is a leader, he would not be a follower of any of these organizations, he simply uses them to get things that he wants.
Which only leaves one person Bob Kirkland, or in this case his identical twin brother. This also explains why pictures were used to show us the original list, instead of just names. "You can trust the list" because Red John's picture is there, even if the name isn't correct, because Bob Kirland and his brother look identical.
