Been there, done it.
Minarelli scooter kits MIGHT work if you can mill things properly- or space things- but even if you can the port maps might not be any better anyway. Maybe those sick ass malossi bridged exhaust kits would be worth it.
I tried so hard.
It's just not worth it. Get an Athena or parma and a big carb and your hobbit will scare you- and you won't have to learn how to make a six volt engine power your tiny 12 volt pump.