Back to the subject of 1950s belt songs, Jule Styne was the master of the form.
"I'm Going Back" is a great example (even though technically it's a pastiche of a vaudeville-type number from an earlier age).
FADE OUT, FADE IN has a number of belt songs written for Carol Burnett (see "Go Home, Train"
. It's from 1963 or 64, but the style didn't disappear overnight. Burnett songs like "Happily Ever After" from ONCE UPON A MATTRESS would also work.
If you want something 1950s and Mermanesque, but less well known than her Irving Berlin standards, try "Gee, But it's Good to be Here" from HAPPY HUNTING. Be warned: all the high notes in the song fall on words with "r" in them. It requires a singer who can handle words like "here" and "warm", etc.