There's nothing particularly exotic about a wiper motor. With the proper mounting bracket and bellcrank length, just about any basic motor should be able to work. It will just be a matter of finding one that will fit in the same general location as the vacuum motor, and can be adapted to work the original linkage going to the wiper arm pivots. A little basic engineering should allow you to avoid all those ripoff artists who have already figured out how to adapt something!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!