I've heard people refer to them and if you google active USB extension you get plenty of hits. They claim to be able to extend a long way past 5 metres. I'm interested to know how successful this is. They appear to be powered from the usb port so not sure if they are any different to a normal extension cable?
http://www.mittoni.com.au/usb-20-5m-...le-p-1321.html