4wd single axle tractor rear axle question

[Sentinel]

Easiest way would be to just grab the stock parts from one of the Tamiya single rear axle trucks like the Scania R470 or the Man or Mercedes singles. Get the leaf hangers from somewhere like ebay and you'd be able to rig it up easy.
I put a driven front axle in my R620 using springs from a single axle truck that have holes in the pack that I just screwed straight through into the axle. I imagine you'd do the same for a single rear axle, wouldn't have to worry about u-bolts then.