http://www.geethree.com
The place for RS-422 control (Stealth Port). Currently they have products for only G4 towers .
http://www.keyspan.com
The place to buy a USB/serial adapter. They make a PCI card that supplies multiple serial ports.
http://www.contourdesign.com/
Sells great mice and the famous ShuttlePro multimedia controllers.
http://www.promax.com/
Sells many things FCP. Take a look at the dedicated keyboard for FCP.
http://www.bhphoto.com
This site contains lots of professional video gear. This is an old, reliable company.