Go check out Global Rankings, which is one of the new features of the 1.25 patch for Quake 3. From their website:

Global Rankings is a flexible system and each game developer will have its own implementation. In general, most games will allow players to create or join a Global Rankings-enabled game. Before joining a Global Rankings-enabled game, the player will have to create a Global Rankings account. Most developers will request only a username, password and email address in order to create an account.

Which is good, because it will minimise stats abuse. Check out a sample Q3 player's profile; pretty good coverage. Looks like its ranked by frags, but also includes things like damage and awards and stuff. Sure, its not as awesome as the QGL stats, but its pretty decent for a hack.