Sure, you can daisy chain up to 127 USB devices together or something like that. Just probably won't be enough bandwidth or juice to run them all at once. Not quite sure how that breaks down to hubs with multiple ports, but a quick google search shows you can go about 5 or 7 tiers deep. What kind of hubs are they? Powered? Which version of USB for the computer and for the devices you wish to plug in?
To be honest with you though, I'd probably just shell out a few bucks and buy a bigger USB hub.
They're non-powered. Every once in a while, I just need a couple of extra ports. I've got 3 or 4 hubs laying around and I didn't want to spring for the bigger one if I didn't have to. One of the hubs is 3.0, two are 2.0 and I'm not sure about the other one.