There is a transformer based circuit that makes any fuzz buffer friendly. The basics are described here:
Schematics & circuits for guitar effects with vacuum tubes and solid state electronics. FREE downloads of schematics such as TS-9, Fuzz Face and other classic rock devices.
www.muzique.com
A demo video of that very circuit can be watched here:
It's a very simple diy project but I'm not aware of a ready to buy product in Germany or Europe.