I am in the market for a used 3500 diesel truck to tow a FW. My search is almost entirely online, as these vehicles in my price range are hard to find locally, therefore I am willing to find one 1,000...
You can buy a set of custom fifth wheel rails from etrailer for a couple hundred bucks that will bolt on in an afternoon, so any truck without a factory fifth wheel prep kit can be equipped to haul a fifth wheel pretty easily.