I upgraded trucks this fall and got an 06 2500 Silverado Crewcab and the back seats in it fold down flat and turn in to a nice lil bed. Its worked out pretty nice for overnight Jeep trips, but that may only work out for me, cause my Jeep only goes where the truck takes it to
My dad has an 06 2500HD CCSB 4x4 duramax, and Holy crap is it a nice friggin' truck
IMO the front seats are extremely comfortable, and the rear provides a small figured guy like me to sleep back there
And to top it off, the Duramax has GOBS of power but you can't even hear it on the highway, so sick!
However in the Jeep I've slept before, but again being small figured I can put the passenger seat forward and just about stretch out all the way. I have a dog bed that stays back there since my dog is with me so much, so I just flip it over and I'm good to go