Do you have the type that threads on or the 2-screw type? Some petcocks from other models have the same threads and will work, the fuel line may exit differently though. If you've got the thread on type maybe a call to Pingel is in order, I dunno if they make metric petcocks, but they may be able to steer you towards an adaptor for one of their units. Price after all that might just be the same as a stocker though. Then there's always the rebuild route, which is reportedly cheaper, but I haven't checked lately.
Best of luck.
-Alan