you know what? i love the genesis, but the sega CD and the 32X (add-on unit) never did anything for me. granted i never even played with 32X until I saw it emulated, but regardless.
I am hard-pressed to think of an actual "good" sega CD game. well not good but "MUST-HAVE" -- there's a couple of interesting titles but nothing that can be passed over in my opinion (never been a fan of RPG's)
Anyway, to the point - I am no techie, but I would suspect sega CD emulation wouldn't be impossible on GP32. Unlikely, but not impossible. Let's put it this way - if the scene blows way up and there's suddenly a huge amount of interest in it, then perhaps, but as it's going, I wouldn't even give it a 25% chance of actually happening (prove me wrong!) Anyway, it 'should' work for the same reason that turboduo/pcEngine CDrom emulation should "theoretically" work : there are already emulators for PC that will play these systems with compressed rips (game data is a couple MB ISO, and the music is referenced as MP3's). So that's what I am going off of, filesizes aren't so terribly huge.. as to whether the GP32 has enough power to run each system, that is another matter and your guess is as good as mine.