Looks like its the rear shackles and leafs for sure. This is the current problem I'm in except I let it ride all lopsided for too long and the shackle snapped right off. Did you get this fixed by any chance? my trucks been sitting in the driveway too long but have no idea what the repairs run.

__________________
2002 Ford Ranger XLT 3.0L 2WD
160K miles still running but immobile at the moment.
MODS: 06 tails, 08 bumper, Ohio rust mod