Start with an panasonice fz-10 toploader that can hold the cd in place. Get a VCD unit for it and a EM256 memory unit or replace stock ram with bigger ram chips.
Unit must look like a retro 3do factory made machine like the panasonice fz-1.
Dpad is nice. But ad an analouge stick from a Playstation.
And a small track ball from a labtop for mouse type games.
Head phone jack is a must with volume control. Mabe ad a karaoke mixer with two little 1/8inch micro phone jacks?
Tv hook ups and extra controller port like the sega nomad!
For the love of the 3DO community! Please make this!!