Hi Malcom,
I believe most of the PIC USB gizmos log into the PC as an HID type device, using generic drivers. You could go with one of the USB interface miniboards like viniculum or even I think Parralax sells one too. Only issue I see with HID is it is a bit slower than Full speed USB, certainly slower than USB3. (USB 3 runs something like 287MBS ). Those devices have their own drivers license.