> Now I'm wondering how much processing would it need to add a greyscale (or any other > color) zoomed in main screen on both sides for those who dislike vertical black bars.
Hmm, yeah, like the processing some TV stations do when they show 4:3 content in the middle of a 16:9 news program or whatever: have the 4:3 image in the middle, and a blurred, contrast-reduced version of the sides of the 4:3 image used as the letterboxes. I'll bet Ryan could do that.