I'm sorry, I can't be of much help, but I'm curious as to what you plan on doing with the light?
Edit:
After a quick google search:
http://www.amazon.com/Logiix-10168-USB-LED-Light/dp/B002NKM27Y
http://www.amazon.com/Logiix-10167-USB-Blue-Light/dp/B002NKM27O
If you're into DIY and you're handy with a soldering iron, you can always get one of these and a spare USB cable and resistor and rig it up yourself (Hint: The red wire in the USB is +5VDC and the black is ground.)