Apparently it's "Katie" as my username changed itself to "katieiswatchingyou"...  Kind of creepy.

Anywho, Betram's hair along with the Sheriff's has "thinned".  Red John is said to have thinning hair.  Betram definitely has some brown in his..

What about Kirkland's twin?  Where's he?  Not sure about the shaking hands with Jane, but I saw a neat video on Youtube that thought Kirkland was Red John.  It takes place at the end of season 3.  The guy in the red shirt appears a couple times in the final scenes.  Kind of looks like Kirkland...

http://www.youtube.com/watch?v=590v4FCm6WU  (NOT MY VID!!!)

Or his twin?

...Please stop watching me kate.