Dry-erase boards?

I'm working on a game idea that would require drawing lines on a board, which could then be erased later for re-use. What I would really like to do is screen printed map (one color) on a sealed vinyl mat (like a battlemat). Does anyone know of a source for a low quantity (say, 50 or 100), screen printed vinyl mats? These mats could be small, around 8"x10" or so.

-Ed