It's safe to say that a lot of people would prefer to use a mysql based user/group table rather than text files. It is way more efficient and also a lot easier for us webadmins to integrate into our websites. I'm not sure why there isn't a plugin for this yet, but I would hope someone makes one soon. I think it's safe to say that who ever creates and maintains a plugin like this would earn a nice chunk of donations (and I would gladly donate!)
