Well, this one's beautiful, if obscure.
http://www.sogreni.dk/Chainguard.php
I plan to put one on a commuting bike I'll be building next year. If you're talking about the guards that protect the spokes from the chain and derailleur on the back wheel, I just bought an old Huret on ebay. I'll just bet there's lots of cool 'over the chain' chainguards there, too!