Wow! I don't remember ever having heard "Tom's Diner" until just now, but the similarities are striking. I don't think that's what it's saupposed to be, though. Perhaps the author of TD had this tune in mind.

I don't know how popular these street organs are elsewhere. On Monday morning, when the store in Holland are closed (sort of an extension of the weekend), this one is wheeled through the streets of residential areas. There are always two or three guys with coin banks, shaking them in time with the music and collecting donations. You can see one of them in the video if you look closely.

When the stores are open, it's nearly always right outside Vroom & Dreeseman.

The tunes are on perforated wooden planks, held together Jacob's ladder style, and the title is printed on the first plank, which I wasn't able to see.