So that's a dead end. You might be able to use some component to VGA adapter that would let you use the PC input where there are more controls.
Black bars from 480p is CORRECT. Nothing broke here. One of the side effects of old school 4x3 displaying on 16x9 TVs. Way too many discussions about that so I will not start another.
I recently bought used a LG 22LH20R 22-inch LCD TV. I know that is a very old model but it really fits my needs. My Wii connected with component cables at 480p looks amazing but I have a small problem with the position of the picture. I have small black bars located at both sides of the screen and as a result I also noticed that the picture is slightly squeezed vertically. It seems that you can't adjust the width or height of the video on component. I have access to the service menu but I don´t know if you can adjust it with that or how. Apparently the firmware is 3.06B. Any help would be greatly appreciated.