Bad move IMHO... I really don't understand. I love S&S equipment, but it seems they don't care much for the prosumer or advanced amateur range. I am a strong believer that lenses are more important than bodies in all kinds of photography, even underwater. And never invested much in bodies but a lot in lenses, bodies need only to be quick to operate, and for uwphoto the main thing about that is having the 2 main controls like the D80, D90... F80 for speed and aperture.
But since the amazing NX-80 housing, that I have just dive with last week (since I sold my DX-D80, waiting for a MDX-D90) S&S failed to give prosumers a nice all aluminium housing!!! The MDXs are the best housing S&S has ever made, the D90 will have a good number of users and S&S is missing the opportunity to be the BEST HOUSING MAKER for the D90 going for the new RDX format. And to dominate the this entry-level market now is very close to dominate the whole market in half a decade.
One of the best things about uw housings are: small size (like the MDX-D300), sturdiness (like MDX-D300), finishing touches (like the MDX-D300). Now S&S comes with a housing for a smaller camera (D90) that is even bigger than the MDX-D300, less sturdy, and of course, the acrylic back will not have the same finishing touch that the acrylic back on the MDX-D300...
And with 2 optical cables??? I don't think it is a smart idea to shoot my flash inside my housing with the Nikkor AF-D 10.mm inside my S&S Optical Dome... light is a lot harder to control than water (that is why professional flutes are tuned with light meters to check if the holes close in a right way, and not water!).
RDX format is perfectly fitted for the D60, where more than likely will have owners shooting with lenses like 18-135mm under the wide flat port. But the D90 is another story, it is a camera that allows people to grow and develop their skills, and to add a good deal of equipment, as a dome port.
If the D90 housing really comes in a RDX format, I will not only NOT buy one (my RDX-D90 will rot on the shop), but I will not recommend it also to my friends and students, and for myself I will actually wait for a better camera... let's say a D800 with 24Mp FX sensor that lets me shoot with the 10.5mm at a 10Mp crop, or a D400 with 16 or 24Mp DX sensor with movie capability and an MDX housing. In fact, I will probably buy another used DX-D80 housing just to wait for the storm to pass.
If you have any contact with Japan, please send them my e-mail. I have lost Mr.Koda's e-mail address, he really helped me once with my super-macro set-up!!!
Anyway, thanks for the heads-up.