My cousin is going cage diving in the Farralones (lucky!) and is looking to bring along a camera. he fears that a point and shoot won't do justice to the event, but that a dslr might just be too much (money, hassle, weight).
No. I don't think most of those cameras even have housings available. I think your best bet is something like the Fuji E900. Be aware that it takes some practice to get good results. Take pictures above water so you know the camera inside and out, before using it on a vacation.
Roger - there are many cameras in the BH link you posted.
It is important to have either a nice compact camera that lets you shoot in manual mode, or to use a dSLR. So he's on the right track. But whatever you decide, make sure a housing exists for the camera!
Roger,
The Olympus Evolt E-300 or E-500 are going for the price of expensive point and shoot cameras on Ebay. The cost for the 300 is around $350 while the 500 is around $450. Ikelite makes a housing for both of them. Olympus makes a housing for just the 300. For that matter the Nikon D50 and Canon XT are both going for around $650.
I don't think your cousin is going to be happy with the cycle time of point and shoots, in a cage, with sharks. I've played with most of the point and shoots and most have some sort of recycle time between high quality shots, focus issues, or just plain shutter lag. Since I own a quality point and shoot and the E-500 I can say there's a huge difference in the state of readiness of even the lowest end DSLR and the highest of the point and shoots.