There are also second party housings available for more expensive digital SLRs, but they're anywhere from $500 - $850. Just look at the manufacturers choose the camera you like & see if they have an accessory housing for it.
I have one for my S-45 and it's a really well made item for the cost. All of the controls have 0-rings, the back has an O-ring & it comes with a tube of O-ring lubricant. The lens window is a piece of optical glass, while the rest of the housing is a poly wonder plastic (probably polycarbonate).
