My favorite inter-war film is Hitchcock's _Number 17_, which I think
came out in 1932. It is easily available for purchase or borrowing
in video, though the print is terrible; the first 10 minutes is really
awful. But it's a fine film for getting at inter- and intraclass
relationships. Needless to say, that was not Hitchcock's intent (the
genre is what we could call dramady).