Bhole is the only DOS emulator which could "technically" be ported,so there is no point in considering any of the others unless you know htat hey might be possible....
a 486 with 16mb ram could run System Shock, and that would be the only game i'd be interested in playing on a gp2x (under a PC emulator), but the problem is, its a VERY complex game... far too many controls for any sort of gaming on the gp2x. (movement, the gui, switching the firmware on and off, etc etc). it'd really be a pain to play.