Noblex (Germany):
http://www.kamera-werk-dresden.de/
URL is right, seems that they are currently updating their homepage.

Another article about this company (history and current product programme):
http://www.photoscala.de/node/4575/pdf

Phenix (China):
http://www.chine-taiwan.com/phenixoptics.htm

Sinar:
http://www.sinarcameras.com/

Alpa:
http://www.alpa.ch/index.php

Arca Swiss:
AFAIK no own homepage, but:
http://www.precisioncameraworks.com/...arca_core.html

And AFAIK Plaubel (Germany) is still producing LF cameras. But they don't have a website.

Edit: Sorry David, time overlapping with your post (Alpa, Arca Swiss)