now that GM has killed the H-1, there is an open niche in the market...
personally, if you need anything bigger than an F250/350, then you need to check the used semi-tractor market...
I'm actually thinking about going this route... we have horses, and frankly, hauling 20,000lbs of Clydesdales and trailer necessitates something a little more robust...
so far, I've found a single axle, single screw Freightliner cabover for about $13,900, and a Peterbuilt conventional that's a couple years older but has a freshened engine for about the same jingle...