By the way, this is the light level sensor we went with: http://www.acuitybrands.com/products/detail/147289/Sensor-Switch/CM-PC-ADC/Photocell-Dimming-Ceiling-Low-Volt
Kind of expensive at ~$140, but when you need it NOW, hehe you usually end up paying through the nose.
Eventually we may end up designing our own sensors, if there is a need . . . Problem is, finding good enclosures for a decent price.