I've had similar experience with Cinellis. My 1965ish ones (64/61.5 cm ctc) have 44.5cm chainstays, the 1972ish one I used to have (60/57.5) had 43cm ones. Interestingly, the 1965ish ones have a 108cm wheelbase while the 1972ish one came in at 102.5cm. Even allowing for the size differences, that's a significant shortening of the overall frame.