The thing might be dead, who knows. You are going to have to swap stuff around and see if the problem follows the unit or not.
What happens if you connect the BCF2000's five-pin MIDI connectors to a 1x1 midi/usb interface? Does the activity LED on the interface flicker when you move a slider?
Does the BCF2000 show up as a USB device inside System Profilers (from About This Mac on the Apple pull down)
You have tried different USB cabes and going direct to the computer without a hub.
Well you did say you tried "everything". So I guess that would include my suggestions