Many thanks to City Room for characterizing one of their articles as a Lost City sort of story. (Technically, they called it a "Lost New York" tale, but the link was to this site, baby!)
And they were spot on. The yarn about a new Chinatown restaurant that uncovered an old sign to Lonnie's Coffee Shoppe, a diner that once reigned at 21 Mott Street, and decided to hang the sign up on their front wall rather than toss it out, was right up my alley. I had never heard of Lonnie's, but apparently it a classic-style diner and it was there from 1956 to the late '70s.
There will always be old signs to discover in New York as long as new store owners remain lazy bastards. Thank God.