Well, this ain't gonna be easy. I took my trash to the transfer station today (my little town doesn't offer municipal trash collection). Found myself parked next to a new Ford F-150 PU, so I engaged the owner in some discussion. The truck is 4WD, and completely stock. And the tops of the bed rails were even with my armpits. That's too high to be useful.
There were no blocks in the suspension, so nothing to be removed for a quick and easy drop. Worse, the springs sit over the axle, so they're fairly close to flat with just a very light load of routine household trash in the bed. It appears that the only effective way to lower it would be to convert to running the rear springs under the axle, and have custom springs made.
Disappointed.