[Christ]

For a truck, a rear swing-arm from a bike w/ either a hub motor or an e-motor chain-attached to drive it...

Use the whole swing-arm, weld in a frame w/ a piece of square stock that will fit your specific class of hitch (class III, to be safe, I'd think, at least for starters). Drill the square stock so that it can be pinned into the hitch, and will still touch the ground, but allow it to be pivoted up and down. (Manually, at first, automatically, once the theory is proven and prototyped.)

The whole setup, given parts and nominal dimensions, would make an S-10 about 3 ft longer. Hardly something to complain about.