I say, make graal GBA, but wait until after nintendo has released the linkup cable for the GAMECUBE so you can connect the GBA to the GAMECUBE and use the modem to get online
And in case you didnt know, nintendo will be supporting roms...but i am not sure how they will do it. But then again, the GBA uses C++ so it would be possible to play NES, and SNES games on it