Badges seemed like a popular request when you asked for 1.3, gideon :)
I know it might take a lot of work though, particularly in defining how/when users can earn badges. Perhaps this could be part of the plugin system? i.e. you have several plugins that query the database for, say, answers over 10 upvotes, or more than 100 points earned in one day, and return the matching users. Then Q2A can take those users and award them the badge if they didn't have it already.
As a plugin, you can include plenty of default options, but then we can write our own as complex as we like!