Rick,
The "Dura-Ace 10" is just a footnote in cycling history now. According to "The Dancing Chain" book, Shimano introduced this in 1976. It apparently was an immediate and overwhelming... FLOP!
No other makers wanted to change all of decades of cycling componentry around to follow suit. So, it just became an expensive novely item used on relatively few fixed-gear track bikes.
Obviously, the conventional 12.7mm (1/2" pitch) spacing has survived this challenge, intact.
Bob Hanson, Albuquerque, New Mexico, USA