I'd say there is a zero percent chance of this ever happening :D The original Apple TV was an Intel Core Solo with 256 MB of RAM and an nVidia GPU, running a modified Mac OS X 10.4 that booted into something similar to Front Row instead of Finder.

Oh interesting, it looks like that geforce had an entire 64mb of gddr3 too, it'd still be fun to see if one could limbo that low, though I agree that save for upgrading the BGA ddr3 of the wii to something more the size of the dev kit had(128mb GDDR3)