Hey, I encountered something looking for something else and remembered you. There'sa bit about moving the position of subtitles for the reason you mentioned.
Check out this guide at Doom9.
"DVDFab - Full DVD Split Guide"
The guide mentions DVD Fab can do this:
"Finally, Move subtitles can be used the change the position of subtitles. Those of you who have certain non 16:9 widescreen movies with subtitles will know that sometimes the subtitles are displayed in a position where you can no longer see them on screen (stretching a 4:3 widescreen picture to fit a 16:9 TV is such a situation). This function allows you to move the subtitles to a position where you can once again see them."
Hope that helps.
Sorry, I can't provide a direct link.