You probably won't find any--the manufacturers don't want to be sued when they ruin your expensive display. If you can't tolerate the grey bars or watching the picture stretched or zoomed, you probably shouldn't have bought a wide screen TV or gotten an LCD instead...
Our set has a mode that progressively stretches only the sides, leaving the center with normal proportions. We got used to using ours in stretch mode pretty quickly because, honestly, SD looks rotten on HD displays anyway, so we just don't care. We don't watch any SD with any concern for image quality.
If your set allows you to scroll the zoomed image, you can scroll it down to see the entire top of the frame. You lose even more off the bottom, but it looks a lot better than cutting off peoples' heads
