How long before someone goes all the way by designing a completely custom motherboard and transplanting the key components onto it I wonder? It's been done for older systems but the BGA parts in the Wii would be a challenge.
This is kind of a Wii ship of Theseus.
There are some nuts people out there like Redherring32 with his TinyTendo project that go above and beyond just putting the components on a new board. He designed the TinyTendo which requires cutting down the DIP-packaged CPU and PPU from the NES into a smaller package. These components were only produced for Nintendo systems of the era and are the special sauce for overall game compatiblity. https://github.com/Redherring32/TinyTendo
Of course that's really just sidestepping the challenge of "how small can you get an actual Wii".
However, the intention of these miniature builds is to preserve the original device, just in tiny form. No emulation involved. As if it was an official product.
https://www.zxc64.com/vsa100_based/0_62911_strange_god_agp_2...