I love my 2006 Chevy Duramax diesel and would not trade it for anything.
If I were going to go for a half ton tow rig I would go for a Ford/Chevy SUV or one of those Dodge ECO-Diesel pickups. For a half ton pickup I would also research a Ford Eco-boost. A Tundra would probably be fourth on my list under the above listed vehicles. It is pretty hard to argue with Toyota quality in my opinion but none of the Toyotas I have experience with have been very easy on fuel especially when towing.
For a shorter trailer I would look for a trailer with dual opposing slides. It is really nice to have that kind of floor space. But it seems like slides eat up cargo room so I guess everything is a trade off.
The one thing I have alsways wanted in a trailer is an integrated generator. I really miss being able to push a button to start the generator and charge everything like you can in an RV. I don't know if there are any trailer out there with an integrated generator? If you are full hookup campers this probably won't matter.