op wrote:
So am I supposed to buy an F350 to pull a 10k fiver? Or does everyone just run them overloaded on the gross but not on axle?
No you don't need to buy a F350 truck.
Keep in mind the payload placard has only been around a few years and most trucks were built before the sticker and don't have one.
I would guess 99 percent of the LDTs out here on the road working (private and commercial) for a living use the trucks GAWRs for figuring how much load the truck can safely carry. In the case of a pickup pulling a trailer the trucks RAWR/tire capacities will carry the load so don't exceed those numbers.
You need to weigh your particular trucks front and rear axles separately. Many 250/2500 Ford/Dodge/GM trucks unladin rear axle may weigh in the 2800-3000 lb range which leaves approx 3000-3200 lbs for a payload. If you go over your RAWR you will need higher rated wheels/tires and rear spring help.
Check out the "2500 vs 3500 whats the major differences" thread by Imarcum in the tow vehicle forum. The F250/F350 SRW is being discussed in depth.