I still can't remember the title, but not knowing might be worth it to read your list again. It's the funniest damn thing I've read all month!
I just read Breed to Come yesterday, and that's definately not it. And the scene that I remember was very early in the book. And it had to have been published in the early 70's at the latest, even allowing my memory to be completely confused about when I read it.
But I do love your list. Now I just need to keep tracking down more books.