Monty,
Good show! Your post really got me to thinking. There is one question concerning the octopus (or general cephalopod eye) that I have yet to find out: Has any work been done to isolate the pigments from the inside of the rhabdomeres? Identify the pigments and their photoreceptivity, and you may have a pretty clear answer about whether or not they can see color. Just a thought I thought I should throw out there.
Sushi and Sake,
John