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)

I think Robert Kirkland is NOT Red John but is a follower of Red John. That's why he killed Jason so that he can't tell Patrick who Red John. Any thoughts?

RED JOHN IS ELLIS MARS,

FIRST
- we know that Red John has had many associates, and some if not all of them
appear to have an almost fanatical devotion to him. How? How could seemingly
reasonable people in every other aspect of their life give up their own logic
for the murderous logic of Red John? The answer is -mind control. We've seen
Jane do it himself (Jane is not red john) and we've seen Rigsby under hynosis,
as well as the Russett potato guy and several others, including Christina Frye
(Christina is not red john). Christina Frye is a therapist, well versed in the
ways of mind control, and yet -she has been mentally overcome by her experience
with Red John. SO, RED JOHN is a master hynoptist, just like Jane is. 

TWO - If you go back through the episodes and
look at all the therapists, hypnotists, and mind-control people, eliminate the
women (red john is not a woman), you are left with only 4 people. 

THREE - The telling episode which gives away the
answer is "Red Moon" the first episode that Simon Baker directed by
the way. At the end of the episode, Todd, the killer, has a message for
Jane. But before Jane can get there, Todd is set ablaze, and then as
dying, quotes the Tyger, tyger poem that Red John uses. 



So why would Todd refuse to kill the patsy
that Jane accused (falsley on purpose) of being the murderer? He had
already killed 3 people to cover up his tracks, so why stop now? The
answer? The patsy was RED JOHN! That's why Todd wouldn't kill him, even at the
risk of implicating himself. And who was the patsy? Uh, just a guy named ELLIS
MARS (remember the episode with ..."...HE IS MAR..." ? And who is
Ellis Mars? He's a fake mentalist (supposedly), someone who predicted another death
would occur after the original three. How could he know this unless he was
either the murderer or controlling the murderer? In addition, he speaks in
"polite speak" just like red john did in the warehouse
"Christina would want me to send her love. She's very fond of you, despite
your differences." This type of formal English isn't used by Brett
Partridge, it's used by ELLIS MARS. Plus, Ellis Mars gives Jane a business card
with a tiger on it, which we see in the next scene as Jane holding it up to the
ceiling while lying on his bed and reciting the words "tiger, tiger".
Ellis Mars fits the speech, the age, the physical appearance, and the set of
skills necessary to pull it all off avoid suspicion. The reason that no one
considers him is that he comes across as bumbling, a fake, a wannabe, and he's
easy for us (and Jane) to dismiss. But this is exactly what RED JOHN WOULD do
-he wouldn't come in wearing a black cape and long moustache, he'd interject
himself quietly and unobtrusively into the scene (think of The Usual Suspects -
Kaiser Sosay). Ellis/Red John is playing a game, using his mentalism as a trick
to gain entry, just as Jane does. Remember when Lorelei told him that he and
Red John are similar? And the name Ellis (not my discovery) can be loosely
translated in spanish as "Ellis = "El es"= "He is"
MARS. It's just that we can't see it because it's right in front of
us. 

Alright, So I can definitely say that Red John is NOT Robert Kirkland.At this stage we know that Robert Kirkland is involved in something but we don't know what! In fact i believe that he might not even be involved with Red John. Think about it this is not the last season and it would be WAYYYYYY to obvious if he was in fact Red John. Heller and co. want to 
keep us guessing and on our feet, therefore we can def. say that Kirkland is NOT RED JOHN. Now it remains to be seen if he is or is not involved with Red John. I do no believe so.

I think as this season comes to an end we will find out what and who Robert Kirkland is/works for.

the identity of RJ has not yet been revealed, i believed it is not kirkland. he's up to something, but i also believe he is not an underling of RJ as well. kirkland has a motive behind this killing.