Is there a site somewhere online where people list used baby gear (specifically I'm looking for a twin double stroller). I tried craigslist and ebay but there is very little there for Germany or Austria.
DS1 Dec 2009 DZ Twins July 2012
Quoka.de is also a great place to look. It's classified ads and you can search by your postal code.
I'm surprised you can't find anything on ebay.de. Their baby section is ginormous! Much bigger than the U.S. ebay. Under Kinderwagen are two subcategories for double buggies--Geschwisterwagen and Zwillingswagen. Between the two subcategories there are over 800 auctions listed.