Sorry, I'm not really sure on all the specs related to the Wii and the 480p.
What I'm curious about is I'm limited to my 1440x900 19" widescreen flat panel for all my pc/tv goodness. Currently I use a Tv Wonder VE card to run GC and PS2 via composite, there is no noticable lag but the quality leaves much to be desired. I'm almost certain the res is is the 320x240 area.
What I'm curious about is getting a transcoder box like the http://www.vdigi.com/ but the real transcoder boxes (not just line doublers) only convert progressive signals to vga through component and no 480i.
So my long-winded question here is once the Wii is told to output in 480p will it always output in 480p. The boot screen ALL Wii games, the channels list, etc etc.... if I never played a 480i GC game on in would the Wii and all Wii games be 480p?
If not the I guess I need to start looking for a bit better tv capture card, any suggestions on a nice 640x480 software encoder tuner card?