As long as I have Singin' In The Rain on my mental queue let me work out something that I started thinking about during the theatrical presentation. Before the spoiler-cut, it amounts to this: does the movie-inside-the-movie, The Dancing Cavalier, make sense?
Here's the pieces we know about the story, as best I can put them together. The start would be the ``Broadway Melody'' sequence, which we actually see, where Don Lockwood arrives as a hick from nowhere, rises into celebrity, is crushed by Cyd Charisse's vamp. After this, Lockwood would be working backstage at a theater, reading old-time French aristocrat adventure novels, and knocked on the head. While passed out, Lockwood fantasizes the sequences which had ben the plot of The Dueling Cavalier, designed as one of many, many Don Lockwood/Lina Lamont pictures where she's a French aristocrat and he's a, well, it's right there on the tin. She can't love him because dictate of society blah blah, he can't love her and so on, and after enough sword fights they end up in each other's arms. That's the core of the story with dialogue that just won't cut it when it's what was actually recorded rather than created by intertitles.
I suppose that more or less makes sense, but then: first, where do the modern song-and-dance numbers fit? ``Broadway Melody'' naturally; maybe another could be fit into the movie before Lockwood gets conked on the head. But where would other modern-song-and-dance numbers come in? A couple scenes done in French aristocrat dress would be showy and appealing enough to catch a 1927 audience's eye (I'd say they'd still fly pretty well today), but might they be made part of a framing story where Lockwood's friends try to revive him as the show goes on without him?
But the show must: The Dancing Cavlier ends --- you see the ``The End'' title card come up --- with Lockwood in the French aristocracy setting. This wouldn't be the first movie, even then, to forget it had a framing story, since it's eighty minutes or so from the setup to the conclusion. (The Horn Blows At Midnight wouldn't have been dragged down so in its last two reels if we could feel the movie had forgotten its framing device.) But if the picture comes back to the present-day stuff for dance numbers it's harder to forget the frame. In which case where do the modern-dance bits come in?
Trivia: In 1927 Edward Franklin Albee, vaudeville circuit manager, banned his acts from appearing in talking pictures. Source: No Applause - Just Throw Money: The Book That Made Vaudeville Famous, Trav S D (D Travis Stewart)
Currently Reading: The Wave Watcher's Companion: From Ocean Waves To Light Waves Via Shock Waves, Stadium Waves, And All The Rest Of Life's Undulations, Gavin Pretor-Pinney.