Long bed, short bed, or 5.5' bed?
Shorter the bed, the further back the center of gravity will be. A good assumption is that all the weight is on the rear axle, unless it's a long bed, in which case you may get some on the front axle.
Either way, if you're intent on following the numbers, youll be hard pressed to find a pop up cab over that works. That said, I wouldn't be the least bit worried about putting 1500-2000 lbs in the back with good tires and some air bags/helper springs/Timbrens, etc.
Many of the folks on here will tell you that is totally irresponsible.....meh. If the truck is in good shape, it'll haul that much every day of the week and twice on Sunday with no ill effects.
FWIW, I've driven half tons for years on end with that much weight in them day in day out. That's what happens when you use a truck as a truck. Until the past couple trucks, all of my half ton company trucks would get some rear suspension help first thing and then get used like a truck.
JMO.
