Here are some great photos by Scott Evans using the NEX-5. He has taken his NEX-5 to the waters of the Red Sea and Gibraltar protected by the Nauticam NA-NEX5 underwater housing.
Here is a video of the Nauticam NA-NEX5 housing in action.
Sony NEX-5 with Nauticam Underwater Housing Video
Don't worry NEX-5N users, there is an NA-NEX5N underwater housing.
Nauticam Housing for the NEX-5N
Check out more of Scott Evans' NEX-5 photos at scottevansphotography.co.uk.
More info about the underwater housing at Nauticam USA.