Did you ever try the product called "Rain-X?" It works to a point. Keeps the water and snow from sticking to the windshield. It may be a cheaper alternative until you work out your rear wiper design.
Hey, CAD guys. What CAD packages do you use?
AutoCAD (or as I like to call it, Dino-CAD)
ANSYS (not a lot)
CADKEY (not a lot)