Thx for this example as well. I just re-orgd a lot of the Spelling code, which fixed this example. Keep 'em coming!
Google, Yahoo & Bing all now often show you results for what you didn't search for, automatically. I specifically decided not to do this, but if you don't, you really need to have good 'did you mean' stuff.
I've gotten several complaints comparing with Google on queries where they obviously misspelled, but Google did show the correct spelling automatically. Clearly, it's hit or miss but I prefer the did you mean and showing the misspelled results.
I'll think about open sourcing this piece.