I'm pretty sure there are German sprocket manufacturers. Here in Bulgaria most often we use these guys:
http://nhm-bg.com/index.html
Their catalogues:
http://nhm-bg.com/cata_bg.html
http://nhm-bg.com/catalog/front.pdf
http://nhm-bg.com/catalog/rear.pdf
Check items 134 and 237 from the rear catalogue. But they can basically make you whatever sprocket you want if send them a drawing. Prices depend on sprockets, but I guess a front and rear set should be about 30-40 euro (I repeat, "I guess"). In your case the shipping probably will be excessive, but I can help you with that (and order to NHM if their English is not good enough).