instead of porting some PC DOS games (like wolf3d, scumm engine...) why not porting (or creating) a PC emulator?
even a 286 12mhz with vga display (256kb memory), adlib sound and 2mb of ram would be enough to lot of fabulous games like all scumm games, epic, lemmings, keen, CIVILIZATION and lot others...
it is the game to port really when i think about it: CIVILIZATION!!! B)
there is freeciv which is open source...