This is something I've been working on for a couple of hours now... but I had the idea for it a few nights ago when I was doing some 1v1's on the Halo 4 ladder. Although a pure ladder can't be possible (yet), because we can't do cross server duels, cross faction duels are possible. So, we can do leader boards for each server. And I'll be doing top 10 world wide based on win ratio in combination with most duels completed. (the exact math is a secret, unless you know math then you can figure out.
*UPDATE* DROPPED EMPHASIS ON 1v1's