We traded our fifth wheel in for a Winnebago Vista 27'. I bought an 87 (nice) Suzuki Samurai for a tow vehicle. I would like to sell my Dodge diesel, and the Samurai and get a 2008 - 2012 pickup as ...
Because of the weight restrictions you've noted, the GMC and Silverado will be slightly too heavy, although if they're 4WD they can be towed four wheels down.
Personally, I'd wait until the new Colorado and Canyon come out. They look very attractive and will undoubtedly have the same wheels down capability that their larger brothers have.