Is it possible to connect 50 - 100 of these units to 1 raspberry pi via USB hubs? If so what usb hub would be the best quality?
Yes you can, but don't do something like
this. Each usb device uses ~500mW. Most powered USB hubs will only have a 4A power supply, so they're only useful for about 8 units or so. This means that your 10+ port powered hubs are useless, but the 7 port ones can still be used.