That's only the newer pennies apparently, is it easy to get old pennies? You might chainload a huge bunch of pennies with a penny sorting machine and that might be worth it at a large enough scale.
In your profit calculation, you also need to consider the cost of the energy used in melting the coins.
A munchkin is someone who follows the letter of the rules of a game while breaking their spirit, someone who wins by exploiting possibilities that others don't see, reject as impossible or unsporting, or just don't believe can possibly work.
If you have done something that everyone around you thought would not work, something that people around you didn't do after they saw it work, please share your experiences. If you tried something and failed or have ideas you want to hear critique of, likewise please share those with us.