I might double dip. I have a Retron 5 on it's way(supposed to come out in April sometime), so I can also play my GBA games on that.
BTW, didn't Nintendo say something that, in the future, a lot of these games will also be compatible with 3DS? I thought I heard they are eventually going to make it more open by having a LOT of the games(NES, SNES, GB/GBA and DS) work on both WiiU and 3DS(kinda similar to what Sony's planning, where you could eventually play Vita games on PS4).