There used to be a brand called "Gold Circle Coin Condoms" that came packaged in a metal case, it looked like a gold coin, of course. You could follow that example and get a Condom Tin.

I personally wouldn't recommend putting a condom in your wallet, even with a hard shell, that's a lot of pressure from your ass sitting on it. But there are plenty of other approaches. I looked around and found a case for an iPhone with a secret compartment in the back. Judging from how hot my iPhone gets when I play games on it, I don't think this is a very good idea either.