No, is not possible. Wii run GC games because have a dolphin processor but for wii games uses another more advanced processor, so GC do not have the required hardware
Simple DSiWare doesn't really use many resources which allows it running on the predecessor.
Now you want to do the same with simple Wii games? Both consoles have a PowerPC main CPU and a similar ATI GPU so the idea sounds plausible.
As a non-developer I don't have the faintest idea how an inverse Nintendont hypervisor would look like (and if it is possible).
I would suspect a lot of simple Wii games theoretically…
…to run if re-compiled for GC with minor adjustments. A lot of the shovelware discs aren't remotely full, so they would easily fit on 8cm DVDs. However, unlike the DSi, the Wii is a full upgrade over the previous console in any technical part you look at; not just a small same generation improvement (You can see this on the number of DSi exclusive retail games).