You might want to take a look at cases from Ewa-Marine. They are basically heavy duty plastic dry bags in 3 strengths splash proof 10m and 30m submersion with clear glass view port that screws to your cameras filter threads(you may need adapter rings). They are not very expensive but do work. I had a 10 meter bag(that I used as a dry bag splash proofer) that lasted for several years until it got cut by a mountain bike in my car.
