WSUS Alternatives?
Solution 1:
The German mag c't once wrote a script called WSUSOffline to apply WSUS updates without internet connection. I never used those but you can find it here http://www.wsusoffline.net/
Solution 2:
At my department we use unattended / unattended-gui for initial Windows installations. Its final act is to setup wpkg, which we use to handle updates, new software, etc.