This is why I think Michael Kirkland is Red John:
Since they kill Bob Kirkland and leave us with his twin-brother story, there has to be a reason why, besides giving Bob a reason to hunt Red John (Not knowing it's his brother). If Bob Kirkland has hunted Red John for so long, why wouldn't Red John just kill him earlier?
I think this next episode will give a final explanation to the list.
The remaining 5 suspects:
Bret Stiles (leader of visualize/possible tyger-tyger)
Reede Smith (tyger-tyger)
Sheriff McCallister (old fart)
Ray Haffner (visualize/possible tyger-tyger)
Gale Bertram (possible tyger-tyger)
Jane has them at gun point, which means none of them are going anywhere, and he will see their shoulders. Nothing else would make sense. It’s the only card he’s dealt.
Red John luring them there, to kill off the Tyger-Tyger crew and/or people from visualize, which means Red John is either Bret Partridge or Michael Kirkland. Figuring Jane would check if Partridge really was dead, it has to be Michael, which is why they gave us his twin story. The tattoo could be anything. Ray Haffner said he had other clients after leaving the hotel, which means he could have hired the blond to spy on CBS and then kill her. He might have the tattoo, but that doesn’t mean he’s Red John. Would Red John really need to hire the blond to bug the office, when we know he's more resourceful than that?
This makes sence when you think about the Tyger-Tyger guys killing Michael’s brother. An explosion is a good revenge for Red John (Michael).... Who knows, maybe Jane gets a phone-call to get the hell out of there before it blows, leaving all 7 suspects dead.
This technically means he was on the list as Bruno Heller said, but really only the face matched.
The leverage part could incline that Jane knows. Knows that the tattoo doesn't belong to Red John, but one of the suspects are so important to Red John, that he wants Jane to kill him because he may know his identity. That is why he said he had his leverage, not that he knew who Red John was.
Either way, the tattoo could mean nothing even if Michael isn't Red John. Could just be an attempt to make Jane kill someone.
I still hope Bruno Heller lied, and Cho reveals himself as Red John!