on a similar note, can somebody on good terms with the regen guys get the proper megadrive sprite masking algorithm? the one I have works with many of the difficult cases (pirates gold, galaxy force 2 etc.), but falls apart for some simple ones like the SOR status bar. None of the documentation I have seems accurate and able to handle all cases.
did you check eke's genplus-gx
the guy has done a lot of work on it (and he's always sharing back info, like Arbee well knows for the sound findings)