Yeah, the Canadian penny was discontinued because it actually cost more than a penny to make. Also pennies are useless.
I don't think this is true. Coins are multi-use. Obviously the government wants to pay as little as possible in production costs, but there isn't any reason that the production cost has to be strictly less than the unit-cost of the money.
A relevant quote from the Royal Canadian Mint:
In Economic Action Plan 2012, the Government announced it would phase out the penny from Canada's coinage system. The decision to phase out the penny was due to its excessive and rising cost of production relative to face value, the increased accumulation of pennies by Canadians in their households, environmental considerations, and the significant handling costs the penny imposes on retailers, financial institutions and the economy in general.
(Source - http://www.mint.ca/store/mint/about-the-mint/phasing-out-the...)
I'm not very interested in using Bitcoin at the moment, but I like how its design could enable me to have some representation of electronic currency that could give some of the decentralized flexibility of cash. Perhaps a cashless society could employ structures such as those.