Grigg,
I don't know what year truck you have but I recently saw the Newport system that they have built for the 30's-40's trucks. It is mighty slick but a little pricey. I think it runs in the $400 range. It is a two speed motor with automatic stop. It has two blades and is for trucks with the transmissions over top of the windshield. YOu can probably goggle NEWPORT WIPERS and find out more.
milt mcpherson