Cinelli certainly was not the first to use internal sloping crowns, as these had been a feature of the all-conquering French ALCYON frames in the mid 1930s. Other French brands also used internal sloping crowns but none were as near the early Cinellis in design as those from Alcyon.
Several frame-builders , including Kevin and Ritchie have commented on the several hours of sheer hard filing that was required to remove surplus metal from the Davis cast crowns used by Raleigh, Carlton and amny other builders in the Uk
I built more time-trial frames than any other type of frame and almost all of them were bronze-welded lugless ones..for which I always used an internal sloping model. The Davis crown was a favoutite of mine..I bought them from Ron Kitching under the Milremo brand.
Every time I used one of these crowns it became a challenge to see now slim and aerodynamic I could get it. The fore and aft edges could be reduced to knife edges if necessary because there was always plenty of metal in the middle where the steering column fitted.
I have a couple of examples on my Flickr site, one being on a Reynolds Speedstream aero-tubed Ultimate design and the other being a curved seat tube tandem that used the Milremo crown on the fork but also a second crown to create a straight=bladed fork that I used as a wish-bone device to replace the traditional seat-stays.
The photos are at:
http://www.flickr.com/
Norris Lockley..Settle UK