Aha! Thats a neat solution if the emulators would be good and work, how about GBC emulators?.
I think the gba trimmer was gbata or something like that
@FAST6191 knows better on that matter
As for the gba emulator for nds, here is one
https://gbatemp.net/threads/gbaemu4ds-gba-emulator-for-ds-i-dsi-entry.281715/
I don't remember what the other one was called.. This is a hit and miss, maybe you can play some games with it but don't get much hopes...
You are better in loading this using a slot 1 card if you have it.
If you really want a card for gba, I suggest a everdrive, expensive but it's the best card now... You can also go with a ez iv, also works wonderfully.
If you have a 3ds,you can use virtual console, or gba emulators for 3ds
--------------------- MERGED ---------------------------
Aha! Thats a neat solution if the emulators would be good and work, how about GBC emulators?.
As for GBC emulators, you can use gomba in gba mode, Iirc you can make small ROMS with just a few games
There is gameyob for Nds mode, works wonderfully
Fun fact, you can use M3 game manager to make a gomba file ready to your card