ams (Graz, Austria) has posted details of the TSL2540, a very-high sensitivity light-to-digital converter. Evaluation kit is available:
The TSL2540 is a very-high sensitivity light-to-digital converter that approximates the human eye response to light intensity under varying lighting conditions and transforms this light intensity to a digital signal output capable through a 1.8V I²C interface. The ALS sensor features 2 output channels, a visible channel and an IR channel. The visible channel has a photodiode with a photopic Interferometric UV and IR blocking filter and the IR channel has a photodiode with an IR pass filter.
TSL2540 Ambient Light Sensor matches eye-response – [Link]