I noticed when I made a concentrated "parodinal" formulation including hydroquinone and ascorbic acid to use as a fast 20c first developd I noticed I was getting dye formation after taking it out for reversal via light - the colours were quite strong - I didn't think before then putting it back into colour developer after reversing instead of just bleach and fixing.. so I ended up with black film.
I made it in a hot solution intially so it was ready to use in minutes... overnight though.. still powerful developing properties, but no more dye formation, as I did a test on developing some C41 with it, then a bleach and fix, seems to be staining a monochrome image onto the base after the HQ broke down too much over night.
That particular experiment was a failure, as I cant have dye formation or staining in a first developer, was getting great image development on C41 film a 1+100, 20-24c and 10-12min, as opposed to equivalent development (without staining or dye formation that I noticed) with Rodinal 1+50, 40c, 2 hours.
Going to mix some more stuff up tonight and use it as a negative developer, see what I get.
Glad to know someone else out there is working on something similar. Have you tried developing an E-6 film with it yet? That's what I'm doing. Shooting Velvia developer/wash/blix without a 2nd traditional E-6 developer.