While I realize a bit late (we've just recently launched our community) my organization has faced the same Quality vs Quantity issue. I am managing communities that are inherently smaller, and thus depend on high quality interactions rather than a high quantity of mediocre activity. We have stripped the profiles of any names, as it is misleading and a bit unprofessional (this is a community of executives who don't want to be called newbies). Furthermore, we really try to get member who have posted a question, and recieved a "correct answer" to go back and mark responses as such. This has a high pt value to it and will reward those contributers with quality responses.