What about not scaling to the full size and leaving [black] bars at the top and bottom? Most of the old games will be 4:3 anyway and already leave you with [bla

What about not scaling to the full size and leaving [black] bars at the top and bottom? Most of the old games will be 4:3 anyway and already leave you with [black] bars on the left and right on a 16:9 or 16:10 screens. Maybe one could even make use of the empty areas and put something useful there, maybe darkened while playing in order to not distract. Or just have a decorative frame.