Yes, it can be done! After months of rolling aroud in my bed at night, scheming and planning, i've finally installed electric windows in my Variant, a "Euro Look" '73 412.
The donor vehicle is a 1988 Audi 500SE, and I've used the Vorsprung Durch Technik's rear windows' mechanisms, motors, inner door handles and switches. The installation was suprisingly easily, and it actually works! The windows lower and raise at the touch of a button. O.K., I must admit, I haven't completed it yet, I still have to drill holes in the doors and door sills for the rubbers guiding the cables. These rubbers are from a Golf/Jetta II and has a 20mm diameter with a "concertina" effect i.e. it collapses and expands when the door opens and closes. A friend who is an electronics boffin, is currently building relays for the circuit enabling the windows to be raised or lowered with an "one touch" operation. Eat your heart out, VW Phaeton!!!!
Regards from Sunny South Africa
Pine