I haven't seen a specific "no baggage" check-in point anywhere I've been, but that sounds like a good idea.
I remember when the check-in machines first appeared they also printed your baggage tags for you to stick around the handle yourself but they seem to have moved away from this system for some reason. That seems to me something that could speed up the drop-off.
On the other hand, I normally travel with only carry on bags. There's often little to no line at the "no baggage" check ins, which makes it a much faster choice for getting through the airport.
Can anyone else confirm/deny these observations?