One just sold at the recent Stout auction so auctions may be your best bet to find one. You might want to register with all the auction houses to increase your chances.
I do know someone who will be liquidating an estate that has one but it is part of a set that includes the station sounds diner. He has tables in the silver hall, at least he used to, and may decide to take the set there. He also sells at the firehouse.
