Hi everyone,
David, Stas, and I had a little time for a face-to-face chat about this last week, and we sketched out a basic framework for treating all of these options in a fairly modular and more time-efficient way. There are some things to work out (e.g., "did you mean" is weird enough to require more thought, and we didn't quite figure out how to choose what results to show), but it's shaping up.
It's still here:
I'm going to make another pass at the open questions on the talk page and incorporate anything else from there that needs it.
More comments and questions here or on the talk page are welcome!
—Trey