I only have a 53-12, but I use it often dropping off the steeps here in Austin. I can maintain contact up to 55 mph (~160rpm), but not for long.
Funny how hills dictate a wider range. In the flatlands, seems like you'd never need anything smaller than a 13. The only time you'd go really fast (above 35) would be in a sprint, and those should be really high RPM anyway.
I guess motorpacing can be helped with a tall gear too. I was on a cement mixer for a mile last week at 40-45mph, and 120-130rpm was getting a little tiring given how much power I had to develop to hang. An 11 would have made it a much easier job.