if you felt bold, you could disable all of usb service and then reenable. i I believe that will do it. will also kill keyboard etc.
kextunload IOUSBFamily.kext; kextload /System/Library/Extensions/IOUSBFamily.kext
kextunload IOUSBFamily.kext
kextload /System/Library/Extensions/IOUSBFamily.kext
it will take some more discovery, but i think this might be a good path. let us know if you experiment
all usb extensions in 10.8 at least: /System/Library/Extensions/IOUSBAttachedSCSI.kext /System/Library/Extensions/IOUSBFamily.kext /System/Library/Extensions/IOUSBMassStorageClass.kext
/System/Library/Extensions/IOUSBAttachedSCSI.kext
/System/Library/Extensions/IOUSBFamily.kext
/System/Library/Extensions/IOUSBMassStorageClass.kext