e: On a tangent, the Nintendo DS homebrew scene did end up with a standard (DLDI) for accessing flashcart storage, including the SD/CF slots on some GBA flashcarts -- so you would not have gotten 8 GB of RAM, but if you paid through the nose, you could potentially have made your DS swap out memory pages to an 8 GB memory card :V
e: On a tangent, the Nintendo DS homebrew scene did end up with a standard (DLDI) for accessing flashcart storage, including the SD/CF slots on some GBA flashcarts -- so you would not have gotten 8 GB of RAM, but if you paid through the nose, you could potentially have made your DS swap out memory pages to an 8 GB memory card :V