I'm thinking of selling one of mine. Probably a Canon Powershot/Ixus S500. The CCD on this failed a while ago, but Canon held up their hands and admitted liability for CCD failures on this and 8 or 9 other models. Mine was repaired free (new CCD and lens assembly, which is most of the camera) and I've only had it back two weeks. Works perfectly and produces very high quality results. I also have Canon's own underwater housing for the camera and will sell the two together.
I'm very pro Canon despite the failure (look at how they accepted responsibility) and am buying their G9 as a replacement. Much higher technology, larger, heavier, and correspondingly more expensive. I also have other Canon cameras, film and digital. Superb make.
I have some Casio EX-Z55s with underwater housings that I may be persuaded to sell, though they do everything I want so I'm not highly motivated.