The key to the ignition lock on my '27 Landau Sedan is long gone. Can a locksmith make a new key? Or do I have to get a new lock? Does anyone have a recommendation on a good locksmith?

Try Jarvis Erickson in Washington. He has a Services Offered ad in the G&D each month.

If you take it to a locksmith those that know what they are doing can cut a new key to suit. You may have to take the complete lock.
Tony

And....there are very few locksmiths that know what they are doing.