I am planning to do this soon. although what im doing is probably simpler then your install. im keeping the factory head unit because it integrates very well with the car and looks nice as well. im spending more money then I should as well. in order for my setup to sound near perfect is to buy an audio processor (Audison) and 2 amps. this further simplifies the wireing.
I want to stay away from an aftermarket headunit because most of them don't integrate very well. but yes it is a can bus set up. there are plenty of steering wheel control modules on ebay and amazon. researching these items would take up 2 or so hours of your day. and you will need a double din face plate for your kk. those are specific. get the 09-12 version. I think the 08 liberty has a weird radio installed in it.
im a bit of an alpine fan boy. if I was going to replace my head unit, it would be an alpine.
and reusing old headunits is a risk on your part! by a new one while your online searching for the steering wheel control module.
heres a link that would help you out a bit. its for a kj, but the parts would be almost the same.
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=16048