Here's a way to search for Jewish roots that might not have occurred to you: Researchers have found genealogically relevant Judaica on eBay. A Polish-based auction site, Allegro, has also been a source of interesting items for researchers.
According to one such researcher, you don't need to be able to read Polish to use Allegro. Just type "judaica" in the search window "Szukaj."
Participants in various JewishGen discussion groups are reporting their finds about both auction sites, so do check the discussions out.