Cross-dressing for fun and profit

TCM is showing Some Like It Hot this afternoon at 4:00 PM ET. It is one of the great American comedies. The story, of course, is that Jack Lemmon and Tony Curtis play down-on-their-luck musicians who witness the St. Valentine's Day Massacre in 1929, and need to escape the Mob, which the do by dressing up as women to join an all-girls' band. Cross-dressing is a tried and true subject for comedy; indeed, I've mentioned a few of the cross-dressing comedies before:

Tootsie, in which Dustin Hoffmann dresses up as a woman to get a part on a soap opera.
A Midsummer Night's Dream, in which Joe E. Brown (who also appears in Some Like It Hot) is part of an all-male acting troupe.
Love Crazy. William Powell shaves his trademark moustache and dresses up as a woman to stay ahead of the police, who want to take him back to a mental asylum; Powell gets in trouble though when the ball of yarn he uses for a fake boob gets caught on the spindle of a record player.

Women dressing up as men for comedy seems to happen a bit less. There's the more recent classic Victor/Victoria, with Julie Andrews donning men's clothes so she can play a man playing a female impersonator in the cabarets of Berlin.
In Sylvia Scarlett, Katharine Hepburn cuts her hair and plays a boy in order to evade the law, alongside her father Edmund Gwenn.

There's cross-dressing in mysteries, too. Psycho would be the best-known example of this, although my mentioning it gives away a key element of the plot. (Of course, this being Psycho, everybody already knows the plot, don't they?)
One mystery in which the cross-dressing doesn't give away the plot would be Nancy Drew, Detective, in which the child detective, played by Bonita Granville gets boyfriend Frankie Thomas to dress as a woman to evade the bad guys who are watching them.

Serious dramas involving cross-dressing seem to be rarer still, at least from the classic studio period. One of the few I can think of is Queen Christina in which Greta Garbo, playing the Swedish queen, dresses up as a man (and shares a bed with John Gilbert).
Before you ask, I don't consider Glen or Glenda serious drama.