Flip kit isn't that practical I don't think, but you can get longer Chevy shackles that are used to LOWER Chevy's but raise Rangers (because of the different configurations).
The problems with major shackle changes are pinion angle. The Ranger has a pretty long rear driveshaft which is good, but still you'll need to do wedges or reposition spring perches if you get too jiggy with longer shackles or shackle relocation downward.
I believe zabeard also moved his forward-most rear leaf spring mounts downward using a mounting plate and braces to keep his pinion angle correct. If you're handy with a welder it's an option but it'd be iffy to try to do all as a bolt-up.