[url="http://www.hotwire-bass.de/index_en.htm"]Click[/url], then look for 'Basses', then 'Double Bass' (you cannot copy the exact link).
Hotwire, however, has this bass called double bass. they wanted to emulate a doublebass sound. there are some soundclips, which don't sound very uprightish to me. but it's a very interesting bass, if you ask me. So if you got enough money, send them an email and they will send you the bass for free (well, you'll have to pay the shipping), so you can test it.
And, I have to agree to the previous posts: rotosound nylons!!!!! great strings, but huge gauge, so you probably have to modify your nut.