Could take a look at this:
All NTSC-U VCs and Wiiware wads to date.
Were can I find alot (or some) Sega Dreamcast wads??? please help
There is no DC wads hahaha
Dreamcast games came on GD-ROM which were around the capacity of 1.2GB, good luck fitting them on the Wii through wads.
I don't think the Wii is powerful enough to emulate a Dreamcast which had a 200Mhz CPU.
Not really doing much Wii stuff these days.