“This is an elegant hotel—room service has an unlisted number” is an old joke about hotel service. It was first said about the Fontainebleau Miami Beach in 1956: “The Fontainebleau is so exclusive that its room service has an unlisted number.” No source was credited for the joke.
 
New York comedian Henny Youngman (1906-1998), known as the king of the one-line joke, wrote in a “My Favorite Jokes” piece for Parade magazine in 1959:
 
“There’s a new hotel in Miami that is so exclusive you have to take a shave before you go to the barber shop…Even Room Service has an unlisted number.”
 
Youngman would tell the joke about hotels in other cities—wherever he was staying. Another hotel joke in the same Youngman routine is, “A girl was knocking on my hotel room door all night. Finally, I had to let her out.”
 
   
Wikipedia: Henny Youngman
Henry “Henny” Youngman (original Russian surname Yungman) (March 16, 1906 – February 24, 1998) was a British-American comedian and violinist famous for “one-liners”, short, simple jokes usually delivered rapid-fire. His best known one-liner was “Take my wife—please.”
 
5 January 1956, Morning Advocate (Baton Rouge, LA), pg. 3A, col. 4:
Surest mark of success for a Miami Beach hotel is that it is the butt of stories. None ever reaped such a harvest as the tremendous new Fontainebleu, where they have ballpoint quills on the desks in the suites. The latest: The Fontainebleau is so exclusive that its room service has an unlisted number.
 
17 May 1959, Augusta (GA) Chronicle-Herald, “My Favorite Jokes” by Henny Youngman, Parade magazine, pg. 4(?), col. 1:
There’s a new hotel in Miami that is so exclusive you have to take a shave before you go to the barber shop…Even Room Service has an unlisted number.
   
Google Books
Poultry & Eggs Weekly
Volume 41
1960
Pg. 195:
They tell the story of the new Miami Beach hotel that is so exclusive that Room Service has an unlisted number.
 
Google News Archive
1 March 1968, The Press-Courier (Oxnard, CA), “Toot Loose on Desert” by Bud Tucker, pg. 12, col. 1:
The living is easy at Palm Springs but it is not cheap. Gene Autry’s Melody Ranch is not what you would call a slum area. Room service has an unlisted number and the towels are so thick you can hardly get them in your suitcase.
 
Google News Archive
29 July 1968, St. Joseph (MO) News-Press, “Considine Gives Report on Russia” by Bob Considine, pg. 4B, col. 7
Room service has an unlisted number, apparently.
 
3 March 1969, Chicago (IL) Tribune, pg. B7:
Then there’s the expensive hotel so exclusive that room service has an unlisted number.
 
Google News Archive
21 March 1974, Miami (FL) News, “Henny Youngman keeps ‘em laughing” by Alex Ben Block, pg. 5B, col. 1:
“The Playboy Plaza is so elegant,” says Youngman, “that room service has an unlisted number. “
 
Google News Archive
18 February 1977, St. Petersburg (FL) Times, “Take this story…PLEASE!” by Jim Willse (AP), pg. 4D, col. 1:
(The following is from a Henny Youngman comedy routine—ed.)
“I’m staying at a lovely hotel here in town—room service has an unlisted number. My room is so small that when I put my key in the door, the window broke. All night long, there was a girl knocking at my door. Finally I had to let her out.”
   
Mellow Humor
13 JUL 2012
Henny Youngman Quotes
Posted by Bill_At_Mellow_Humor
(...)
This is an elegant hotel! Room service has an unlisted number.