Are there any open/free downloadable translation databases, besides wiktionary?
(any language welcome)
You could try contacting IATE. It's the European Union's database and it might be readily available. It being the EU you might have to wade through a couple of Red Seas of tape though :)
Another good source could be Glosbe, who are trying to build a large dict based on translation memories. According to their about section they allow downloads of the translation memories as well, so try contacting them.