Yeah, that definitely sounds like a possibility. I also wonder if any of the ports are tied to the same bus–it is a cheap laptop after all. I am going to have to dig into the manual and see.
I thought about trying three cams each in their own USB port anyway, but then I don’t have a slot open for a mic after that (it has reliability issues if I plug it into the powered HUB, so it needs to go into the computer). I should try it regardless just to see if the third will come up at that point.