I'm big on the "do it yourself" bit. It's also called "Cheap".
I will buy things that I can't make but the wiper motor is one that I was able to tackle. The wiper motor I used came out of a Pontiac Fiero. No particular reason other than it was readily available when I decided to do the modification. I don't think it will fit into the existing hole but it wasn't necessary since I planned on mounting it behind the fender to clean up the firewall.
The trick to making it work was removing the wiper switch from inside the Fiero steering column and mounting it behind the dash. To do this I made a simple bracket that allowed me to combined the 68 wiper housing (gutted) and the Fiero wiper switch. I then removed the plastic from the Fiero wiper switch stalk and took the remaining metal stem and mounted it to the 68 knob using the factory set screw. You'll need to get a copy of the switch/motor wiring diagram to finish it up.
The 68 housing gave me the ability to mount the switch to the factory dash without any modifications and since I used the 68 bezel and knob, you can't tell it's not the factory switch.
If this doesn't help, I hope it at least inspires...