Hey! I've been curious lately of what the trimming capabilities of the Wii mini are.
If anyone knows, do tell. If not could you link me to some schematics of the board layers?
Some people are working on it, but IIRC it's not too promising. We only just got bluebomb, and the mini lacks easy access to various traces needed for portablisation. For portables, the mini just isn't currently viable and may never be.
In theory the board would be able to be trimmed very similarly to a 4 layer, however the orientation of some of the components would make the outline a bit larger. We generally don't recommend trying much with wii minis just due to their higher rarity compared to any other kind of wii.