If the idea of b&w slides makes you salivate, check out ilford's manual for reversal processing of FP4+ on their website.
To summarize, you first dev in paper developer, bleach in potassium permanganate + sulfuric acid, clear the bleach with potassium metabisulfite, re-expose the film to light, develop to completion in paper developer, and fix it for good measure.
I've seen a harder-core recipe that incorporates potassium dichromate and uses sodium bisulfate in lieu of sulfuric acid (easier to find, it's a pool-store type chem), but chromium(VI) is pretty toxic.