If anyone is still looking for an affordable Camera housing I would recommend Epic Camera Housings (http://www.EpicCam.com) They are lightweight easy to use and work with a wide range of video cameras.
Full disclosure I work over at Epic.
-Holsum
A good way of testing waterproof housings is toilet paper. Fill the thing with toilet paper first. The slightest bit of moisture just destroys it and is very obvious to see.
Do you really want to lug the VX2100 on a rafting trip? I gave my wife an Olympus digital camera (also does some video) that is waterproof to 30 feet (actually works underwater with sound) and drop proof from 5 feet - You can see what it does here - http://birdcat.com/video/pool0608.html
I find it works fine for family stuff (not professional level as it only captures 640 X 480) so I guess it would depend on what you're trying to film.