Hi,
I just saw this on a German Mac-related web site with a classifieds section:
http://www.macup.com/kleinanzeigen/anzeige/40688/"Biete eine Nextstation inkl. Monitor (Original) + Tastatur + Maus. 1a in Ordnung und einsatzbereit. Externe Festplatte vorhanden. Nextstep 2.1, Mathematica, WordPerfect"
(NeXTstation including original monitor, keyboard and mouse. Fine condition, working. External hard disk. NeXtstep 2.1, Mathematica, WordPerfect)
I'm not related to the seller, just thought I could pass this on in case s/o here is interested. It seems that you have to register with the MacUP site (for free) if you want to contact the seller.
-- Michael