Most people are saying that Kirkland either IS Red John, or associated with him, but what if it is something completely different?  

I'm just trying to play devil's advocate, but what if Kirkland is really a good guy and is trying to find Red John?  Maybe Kirkland knows who Red John is(or is close), and was afraid that Jason knew that Kirkland had found out, so he asked Jason if he knew who he was to make sure that he hadn't told Red John that Kirkland knew who he was.  (reading that back, it might be hard for you to follow what I'm trying to say...)
I'll try to explain that a little better:
Kirkland is hot on Red John's trail.  Maybe Kirkland snuck into a meeting where RJ and Jason both were, dressed in a disguise...He found out, or is very close to finding out who RJ is...He wants to make sure that he truly went un-noticed, so that Red John doesn't think that he knows who he is, cuz if RJ knew that Kirkland had found out, he would be dead.  

Hopefully you guys understand what I was trying to say there, i realize it is probably hard to read the way I wrote it out, but it makes sense in my head.

I just keep getting the feeling that Kirkland is a good guy.  It seems to me that they are building him up to be one of RJ's accomplices, only to surprise us by revealing that he is actually going to help Jane and the CBI catch Red John in the end.  The only glitch in that theory is that he killed Jason...that makes it kind of hard for him to be a good guy, even tho Jason was bad. (but maybe necessary so that RJ doesn't find out)