I have recently discovered this wide dynamic digital light sensor on mouser: bh1745nuc-e: 0.005 lux to 40000 lux, 4x channels: green, red, blue and white!
It was so tempting I could not resist designing a light-meter probe for my enlarger (based on a PIC24LF microcontroler and a DOGS LCD screen)
This looks great. I can't wait to see the progress. I hope you can offer links to the PIC code and PCB files. What kind of enclosure will you be putting it in?