Hmm, I just posted a note an hour or so ago asking about user-specific attributes (as in OpenACS 3.x), rather than group-specific attributes (as seems to be the default in OpenACS 4.x). It sounds from this discussion as though the user-profile and/or profile-provider packages are the way to go.
Unfortunately, I also don't see either of these when I check out the latest CVS version. I'm sure that I'm missing something obvious here, but a clear explanation of where to find these packages would be greatly appreciated.