Probably not want you want...I did a DIY 4 port powered USB hub (actually just used the PCB out of a mono price USB hub) with +12V distribution and +8V out for a DSLR power.
I had to build in a +5V PSU for the USB hub, and a +8 PSU for the DSLR but this was easy as I already had +12V available. All put in a small box that I made to fit between the OTA and dovetail. Keeps cabling neat and out the way. I use right angle +12V power plugs for DC out so keeps cables real close and neat to the OTA.
I have tested it running all 4 USB ports at once: DSLR; USB to RS232; USB focus controller; and TEMPERHUm device ......no trouble running all that data down one USB cable to my lappy.
There are plenty of spare +12V jacks and the +8V DSLR is a different sized jack....drawbacks...well not enough USB ports IMHO, and the mono price hub I used was not the best USB hub design I've seen.
However, designing and making your own USB hub....it is quite involved!
Anyway food for thought..FWIW
edit:
Oh... I run my dirty DC power (for dew heater controller) thru a different cable at the front of the OTA/mount as far as possible from the clean +12VDC (above). The above distribution system, filtered DC ...squeaky clean, for cameras etc.
Oh and one more thing...I reckon that we should all be looking at something like the "Raspberry Pi". Some folks already have it doing guiding with PHD, but the open ended ability to use one of these for astronomy is limitless (maybe over VNC). What use the Ethernet to control it, it has USB ports, RS232 (via GPIO breakout, although it runs USB to USB to RS232 converters ok..I think) and even a video camera pin port (underdevelopment). I saw element 14 is now selling cases for the Pi.
Really sounds like a project that can be used to accomplish many astro things easily and remotely.