The typical Military "deuce and a half" had a cargo capacity rating of 2 1/2 tons cross country, but much more on the highway. The same applies to the "five ton".
I just saw an ad on tv tonight claiming a payload for a 3500 of 7,222. Sorry, marketing folks, but that is NOT a "one ton" (3500) truck! Being "old school", IMO a "one ton" truck should have a payload of 2,000 lbs.
However, that is not true these days. Perhaps that is why there are no 100, 200, or 300 pickups anymore. they are 150 (or 1500), 250 (or 2500), or 350 (3500).
All such designations are pretty much meaningless now.
Just as a point of interest, I have owned two mid 1970s Dodge W100 power wagons, both club cab short box, that had 3/4 ton axles and springs under them. One of them I did the conversion on. everything out of or off of the 3/4 ton was a direct bolt-on fit under the 1/2 ton, except for one driveshaft. I had to have the rear shaft custom built.