Have you looked for a fellow named moggy on the shop talk forums' forced induction forum. He's in the UK and made his own supercharger kit for his Type IV Bug. He has the plans for it and he can give them to you. It takes some welding...but hey that's not a problem for you
Here is a pic of the setup and a dyno chart:
Dyno
Now I think a LOT of people would be interrested in this as a kit...even more than the Steel Fender Flares!!!
Nathan