usb hub does work, just make sure if you use external drives, they need to be powered.
you can also attach one of those 8 in 1 flash card reader to it if you want. Should read all sources from SD/ MicroSD/ Memory stick etc.
I have not yet tested an un-powered hub. I have one at the office that I'll get and test in the new year and feed back.
Also folks, don't bother with older usb 1.0 hubs. They will probably work, but the data rates may be too slow for your 1080p videos.
A Powered USB hub would be best, less power draw from the PBO and less problems.
Now if only we can select a USB HDD for BT to dowload to?
I can also confirm that a Contour HD (720P) and ContourHD1080p helmet cameras work when connecting with USB.