Very nice. I would be interested, but I would like to see if I could fit a small LED watch face into where the time is for a real clock. Nice design. Have you ever thought of contacting Swinks and working with him? He has well-engineered CFTBL mods (snack bar mod, tail light mod, movie poster mod) through Shapeways and the two of you together might pull of some really cool stuff.
BTTF owners usually have a high attachment to the game due to the movie, so well-executed mods would probably sell well.