1 4 port USB 2.0 hub
4 WebCams
4 16' USB cables
All together this should be about 200.00.
The only drawback I can think is low light levels, USB cams dont do to well with that. But hell get a 1.25 light bulb and place it where the camra is pointing.

Any other reasons you all can think of that would make this solution a bad one?