I thought this was kind of neat. It's a pill box for your key ring, but it looked about the right size for a 123 battery. Waterproof, made of some heavy steel like material, and chrome plated I think. $5.00 at CVS.
It's called the EZY Dose Deluxe Nitro-Fresh. Found it at a lot of places, but it's made of chrome plated brass. Can be seen below and they also make a plastic version for $1.49.