Just did a search at XDA and found this pic of the internals of the stock USB dongle. Definitely some circuitry involved.
One tinkerer reported that the output "hosting" voltage at the 40 pin is 10VDC and the dongle regulates it down to 5V. Not sure my geriatric fingers could readily remove the 40 pin connector on the dongle board and successfully solder a cable in its place.
Will just have to wait for a younger, more nimble person to build these "to order".