I have been using my 7D with my Carbon fibre housing for a while now and have recently made a website to show some of my better shots.
I'm really happy with the 7D and unlike most surf photographers I shoot on Auto focus and the thing never skips a beat. If anyone else uses their canon in the water I'd reccomend getting a Gopro HD cam to mount to the camera. I have recently done this and now have Video and stills of all the waves i shoot, and when making videos It is really cool to be able to incorporate the hi res stills into the mix.
Below is the latest youtube clip to combine 7D and Gopro