AFAIK, these kind of reversal papers are same type of chromogenic technology as RA-4 papers, but optimized for reversal processing, just like C-41 vs. E6 films.

So, even if chemistry is not currently available, some kind of home-brew reversal RA-4 mixes could work quite well in the meantime.

Or do anyone know the exact formulas for the chemistry? Even MSDS might help a lot.