My old Powershot SD 890 IS had these really cool features (discovered accidentally no less) where it would take a black and white image except for one color +/- some range. My newer replacement camera sx210, does not have anything even close to this. I've attached a couple of samples of what I mean. Any way possible this can this be implemented into CHDK?
Also, a second cool related feature was the cameras ability to take a color photo, then substitute one color for another. It could take for instance the yellow beer and change it into green.