Thanks, sounds good enough for me, as I have the new 3ds. But I would like to share the CIAs, so is not good if they run badly on the old. I think I'll stick with Picodrive for my system.
Have you tried with GG Injector? I have a real Game Gear and a pirate cartdrige that holds a lot of Master System games. I think they should be easy to convert, but they might lose resolution.
Also, there's a Master System emulator for GBA, that could be used to make CIAs, but I think is not that good.