Question: Is there a command I can give the Monero daemon to calculate the total of all coinbase transactions so far?

How do block explorers calculate the Monero coin supply and how can I verify their accuracy?

Answer: 
Starting with v0.10.1, there is now a command `print_coinbase_tx_sum` that give you this information.
There is no such command. However, it'd be easy to add. Feel free to add a request for this on <https://github.com/monero-project/bitmonero/issues>