Keep in mind that *ALL* Wii and Gamecube games capable of 16:9 achieve it using an anamorphic solution. That is, the actual output is still 4:3 in terms of pixel ratio and playing in 16:9 simply results in rectangular pixels thereby reducing image quality.
Right, I'm talking they don't even offer the option for 480p, and a few rare ones don't offer that anamorphic solution.