I'm guessing you're going to have to do one of a few things:
- Increase your budget
- Lose the 4WD and/or diesel requirement
- Get a vehicle in that price range that runs, but needs work
If you're looking for a good daily driver, find yourself a big, heavy, good running American made car. A lot of people are ditching them cheap in favor of more fuel-efficient cars. My "winter beater" is a '93 Buick Roadmaster (crunched in the drivers side) that has about ZERO style, but runs great (350TBI), gets 22mpg, and carries/tows anything I need it to. I paid $750 for it, and put about $600 more into tires & tie rod work. It's VERY reliable.
On the 4x4 topic, I got a REALLY good deal a while back on an '80 turbo diesel Scout Traveler (rare). I paid $1000 for it, but had another $275 into getting it back from Wisconsin (ferry trip). Even so, it would have needed work to make it daily-driver friendly.
What's your primary goal for this truck? Daily driver? Weekend toy? That may help people with their suggestions.