Reader Jeffrey R. was kind enough to send us his achievement tracking site, named (conveniently) AchievementTracker.com. We've seen quite a few sites for tracking achievements on your own character out there already (especially since the Armory opened up the information to the web), but unlike the others, AchievementTracker seems to be focusing on ranking only -- instead of browsing over your own information, all the site really presents is a list of the top players in the world, US, EU, or by the various realms.
There are a few caveats, the first being that they're only tracking characters above level 70, and the second being that they're not tracking everyone -- I had to put my own character into the system (though that won't matter if you're just looking for the top players, since I would never even rank on any lists anyone was watching). And while WoW-Achievements has Beelsebub of EU Darksorrow at number one and Minipuff of EU Stormscale in second place so far, AchievementTracker has them backwards (and their point totals are lower -- maybe Armory lag?).
And of course we don't know for sure if there's someone on the realms that neither of these sites are tracking with more achievement points (it may be worth noting, too, that beyond Armory links, neither site tells us much about the characters -- is there a class or spec that's better for achievement point earning?). It'll probably take a little while until we can get a standard for tracking these, but until then, looks like we'll have a few different lists to watch.