I see the quandary involved in defining craft, it's all a craft. It's arguable in fact that the brewers from the big boys are much moreso craftsmen than some small start up brewery, I think the issue is calling it craft beer in the first place.
I also see the problem with defining craft by size, before we know it we'll have "Blue Moons" slipping in under the radar as "stealth" BMC with a craft air.