Consider trying this beta version. Please post any problems (or successes).
The major focus of this new version is to hide the username of privileged users. Which, it turns out, is a lot of work to do correctly.
It includes optional restrictions on password reset attempts and new user registrations. It also lists any privileged users whose username as the various names displayed on the blog. Which by default is all of them as WordPress default uses the username to construct author archive URLs, among other things.
Largest missing piece is functionality to modify username (which might possibly be dangerous to do) and "nicename" (which might invalidate previous author archive URLs).
Also considering making this version 2.8+ which would simplify the code.