Just started running NesterJ and it's great. The PCEP, I'm a hair dissapointed with. The first game I tried, Blazing Lasers, glitched bad at the end of the first boss fight and became unplayable. Also, if you change that one to 4:3 ratio, it seems to gum up the works a bit.
@ boc, I think the complete TG16 set would fill half that gig by itself, so no.
I had to pick and choose, but really do you need 56 crappy SMB graphic hacks? I'm pretty confident you could get the best of those three systems with emulators on a gig stick.