Question from @Timothy_Clark:
From the electrical/raw Linux underpinnings side, those USB ports are
first class USB ports, so adding a hub is on option. The caveats here
are that we already have one hub on the board (so your throughput will
take a hit as messages get routed) and that you should be sure to use a
powered USB hub because those ports are overcurrent protected and will
turn themselves off if you try to power something that draws too much
current (read: mistreat them).
I'm not sure what the story looks like from the software/API side of things... @tim may be able to weigh in here.