I'm thinking about something, but I don't know if it will be possible as you can only install signed cia (or need CFW).
We already have few translation project for 3DS, and it's hard to release patches as all the ROM is encrypted and it would make a very big (illegal) patch.
What would be interesting is using the update system and packing the patched files as cia. patching file would still require user intervention as we can't share already patched files, but it's just a detail for later.
But the generated cia would not install, right?
Do we know where and how is working game update file system?
Anyone tried to generate custom game update files?