They don't, however, track anything but the final achievement of the guild, the Now You're Just Showing Off achievement, and when players got it on each realm, region, and even worldwide. This achievement is kind of the pinnacle of brawling prowess, but it would also be excellent to see rankings for those further down, for example, to see if there's a glut of players stuck on Yikkan Izu or whether it's just that my shadow priest is undergeared, or played by someone terrible at shadow priests.
One very interesting thing about these stats is the prominence of ranged DPS among the higher rankings. Mages, elemental shaman, warlocks, balance druids, and hunters all rank pretty high in their top 100 listings, with melee classes seeming not to be able to keep up with their ranged cousins. Is this indicative of a ranged DPS bias in the Brawler's Guild boss design?
Also, do note that GuildOx's database is still gathering, so don't check your realm and assume that, because it's empty, you can get ahead and claim the top spot! It will take a little while to stabilize and be completely accurate, thanks to how the database works. But do check it out! Like all their ranking information, it makes interesting reading.