One of the access-granting developers looked at the code sample, Extension:Realnames, and had some criticisms, as it tries to find and replace all username links in the page output HTML, and the User::newFromName( $m['username'] ); query in the callback for each match is not batched.
We're really being that nitpicky? I've seen some really shit-quality code committed to extensions, batch calling the User class is really minor thing that (imo) shouldn't halt this process. It's extensions access, not core, he's asking for.
That's what I have to say right now, I might some up with something else tomorrow.