There's a quite interesting game on the "8-in-1 (GD-8XX)"... "Math × ÷" is a Chinese translated, mapper 0 conversion of Sansuu 3 Nen, which is normally a mapper 185 game. This may be useful as a basis for further mapper 0 conversions, I attached a rip of the game below.
Edit: it ended up being quite easy to convert Sansuu 1 Nen to mapper 0 based on this code (as well as the Japanese language 3 Nen), so I have attached those converted as well. I was unable to convert 2 Nen, however.