Mike
I'm still trying to find something myself. One thought is something like the New Port engineering unit or another compact motor and to build some kind of mount to install it inside the cowl. Seems like it should be doable... I also have a wiper unit off a 1996 Dodge truck for my 59 Chevy build which seems like it could be out down to fit inside the cowl as well. Not sure how much fab you're looking to do but figured I'd throw out the ideas.
Heres a pic of the Dodge setup