The original GM 54/55st 6v electric wiper is very hard to fine (with mounting bracket).

Wiperman is the only way to get a vacuum wiper rebuilt with original parts.
I only use his services.

What other types of ideas are you looking for?

Ways to have more consistent vacuum?
- vacuum reservoir (I will try this someday)
- dual-action fuel pump (better than stock set-up for almost constant wiper movement)