Deck Legend keyboards require a maximum of 500mA to function properly which would require a powered USB hub, i.e. one more cable coming out of the housing. This is the reason we do not have a hub incorporated into our Deck Legend product.
For $7 and a bit of cutting, nox771's solution would be my route as well. I highly doubt we could ever incorporate a USB hub for less than a $7 increase in overall price so if you can do it by all means get out the Dremel! You can always pick up a new case
if needs be and modding it (if done properly) will not void your warranty.