Check out what Hobgoblin International have to offer (and here is a link to their USA website - including Citterns). It's a great catalogue, by post or on the web, even if you don't end up buying from them.

Citterns and Irish Bouzoukis have converged - both have courses of doubled strings; citerns tend to have five courses and bouzoukis four courses. There aren't really standardised tunings, but if you play guitar you won't be at sea. Especially if you go in for funny guitar tunings to start with.