Vivian Duncan squeaks "Is that all right??" at the end of Duncan Sisters records almost as often as Annette says "That's all!" These are their cute/annoying little signatures. A lot of artists ended their bits with such a signoff.
On their Victor records, The California Humming Birds - Adler, Kern & Weill - have a quite elaborate musical postscript that sounds like a radio station break.
My Grammy vote for Most Obsequious Signoff of all is: "May it please you - Ben Pollack!"