Slightly off topic:

I've seen where someone transplanted the analog board out of a 575 into a Color Classic Mystic mod (with 575 logic board) and thus got 640x480 on the CC, with rumours (as far as I remember, unconfirmed) that it might be able to go even higher. This required trimming down both the 575 AB and the inside of the CC to make it fit.

I wonder how a 5500 AB would go ...