If you use a carb that's to big, you're not going to see much of a hit on the top end. So I'm sure there's pleanty of fast bikes running 24mm carbs. The question is what kind of fuel mileage are they getting, and how do they run at 1/4 and 1/2 throttle.
Yes, I'll be using a fairly small carb on my bike. probably a 15 or 16, as that's what's convenient to buy.