The only USB + motorized PTZ camera that I'm aware of being still in production is the Chinese cam generically called "USB 2.0 Motor Tracking Camera". They are sold online badged with numerous different brand names, including: "InSight Innovations Motion Tracking Camera", "GearHead PTZ Camera", "Typhoon", and so forth.
I personally have one that's badged "Typhoon" and another on badged "GearHead". They both have the same Chinese guts, the exteriors are very similar to one another but not identical; color & trim differ.
They work fine with the latest AbelCam running on an old XP box. Can't comment about Win7 or Win8.1 as I have not tried them on those OSes.
They are IMO "adequate" cameras but not "fantastic". The motorized Pan/Tilt works fine and is actually smoother and quieter than my Orbits. The video resolution is not as good as the Orbit but it's not horrible. If all you want is 640x480 it should be okay.
Here's a link to a picture of a typical specimen of this camera at a site that doesn;t seem to have them anymore...
http://www.geeks.com/details.asp?invtid=IC825C
EDIT: fixed link