Woohoo! I want one.
I think you could definitely find a market printing these out for popular cars that didn't have OEM mirror blanks available. Last gen Metros, all Prius, all Insight, ? ...
I'd modify mine with a small convex mirror mounted on the blank, though (complemented with a larger interior side mirror). I sometimes have to back into extremely tight spaces and need to be able to see the side of the car.