I am trying to put together a good list of websites for all the best UL gear. I know of all the 'commercial' gear but the smaller private owned sites always have the best gear. They are also the hardest to find. So far I have this. If you know of more, please let me know.

http://www.backpackinglight.com/cgi-bin/backpackinglight/index.html
http://www.mountainlaureldesigns.com/shop/index.php
http://www.titaniumgoat.com/index.html
http://www.gossamergear.com/cgi-bin/gossamergear/index.html