Bruce, I haven't done my shocks yet, so I can't say for sure. But my thoughts were to use shocks for a late model truck. The shock mounts on the rear should accept them as is. Brackets to mount to the frame should be fairly easy to fab, even in the back yard with only a saw,drill and well tuned hammer. They could be bolted in fairly easy, though a welder might be quicker.
Just about any shock for the rated load of the truck should be ok functionally. As with the heavy springs, there isn't a lot of travel.
If you manage to work it out, I would like to hear what you learn.
Ned