The GBA homebrew scene has got hundreds of games, demos etc and now it seems it may be coming to the Dreamcast, heres what Troy Davis(GPF) posted in a DCEmu UK forum Topic

well I have ported a GBA emulator to the Dreamcast(based on Visual Boy Advance). I will hopefully be releasing it soon. I just have to get some stuff cleaned up and hopefully get sound working, and speed playable and figuring out the license GPL etc.

I have played a couple of Public domain roms and 1 commercial rom (Super Mario World ~ 4meg).

I tried an 8 meg rom but it ran out of memory, don’t know if that is fixable yet.

Troy Davis(GPF)
http://storm-studios.net/GPF/