Well, as far as I know, just like on a PC USB hub, each USB port is assigned to their own coding so that when it's plugged in, it will recognize four [or more] different USB ports, and not the same thing with the end of result of only recognizing one port. I don't know too much about the USB sets the XBOX uses, but it seems pretty logical that coding is different for each port and the motherboard will send different signals to each USB port, just like a PC USB hub. I'm sure that this can be mimiced somehow by using the hardware of a Generic USB PC hub. If maybe each port simulated the coding of all four in one, that may work...but hell...good luck with that man. Nothing's Impossible in the XBOX world.
Just my two cents.