Look for the plastic food storage boxes with locking tabs and a silicone seal, like Lock n Lock, Sistema and Mira. You can find some in discounters like TJ Max, but storage specialty shops will have the best selection.
The sealing boxes will protect from rain, dust and bumps. You can add thin foam or even bubble wrap. My favorite combo is a Zing neoprene wrap and a box.
I'm sure they would survive a dunking, but I won't buy you a new camera if you go canyoneering with one :) They are bulky.
Smaller locking boxes are great for point and shoot cameras and small electronics. If your camera box has extra room, you could slip your phone or GPS in there too.