It sounds like you're talking about wireless usb, where instead of a cable, you're using bluetooth to connect to a usb device. There is already a wireless usb specification :
http://www.usb.org/developers/wusb/. I doubt they will make a wireless version compatible with the bluetooth 1.2 implementation since that is very slow. If you want to connect a wireless harddrive, take a look at the ASUS WL-HDD 2.5, which is a wi-fi external enclosure for a 2.5" harddrive.
http://www.hardavenue.com/reviews/asuswlhdd1.shtml. It doesn't run on batteries, so it's not really that portable.