3) Sample colors of edges of unscalable 4;3 bgs or menus, add aumatically generated border that smoothly transits from sampled edge color (with transparent edges that covers original frame a little bit for smoother transition) to black or white (or custom color) vignetted edges. I did such thing manually in photoshop to created widescreen backgrounds for 4:3 games to avoid stretching os some menues and arts. but making things like that procedural in run time will be much better.