Well, my curiosity on this subject remains, but I found out about an awesome one-day sale this morning on newegg that was so good I couldn't pass it up. Class 10, 32 GB card, $9.99, Patriot brand. Wtf. Lol.
But like I said, I'm still interested in the answer to this if you know anything (or any other good sources of Wii technical information you could point me towards. Particularly in the video system, beyond the simple plug pinout. Like a datasheet of the DAC! That would be great, but I don't think it's public.