I would like to complete Digideeps list of underwater housings for the Sony DSLR A-350 with housing from:

Ikelite, model #6841.35, $1500 USD, http://www.ikelite.com/web_two/sony_a200.html
Nimar N303DI, http://www.nimar.it/custodie_reflex_digitali_eng.htm

There is today no information on Nimar website of uw housing for Sony A-350, but you can order it if you send the camera to get it fitted.
I have recently received my new housing for A-350 from Nimar, but unfortunately I had to send it back for modifications I requested (I wanted to get the control for ISO settings exposed).