Is there an underwater housing/casing for my digital camera modeled as Xacti VPC-E6?

Answer 1

You could get a dedicated plastic pouch like this one:
http://www.bhphotovideo.com/bnh/controller/home?O=5237&A=details&Q=&sku=400205&is=REG&addedTroughType=categoryNavigation
Considering the Sanyo is so tiny, you might fumble with the controls however.
I don't know of any hard cases for the Xacti VPC-E6, but if there is one, it would probably cost more than the camera itself. These things are insanely expensive.