There is now an official german sister site for vBulletin.org:
www.vbhacks-germany.com
All users are confirmed as license holders before they can download hacks from this official site.
Once vBulletin.org upgrades to vBulletin 3.5 we will be adding a field for hack authors to tick to give permission for their hacks to be translated to German for this site.
Update August 2007: www.vbhacks-germany.com is no longer the official German Modification website.