In the run-up to Wikimania, I plan to get the single-user-login code base sufficiently up to stuff to at least demo it at the conference, and to be able to snap it into action probably shortly after.
Milestones:
1) logging in on local DBs
2) new account creation on local DBs
3) migration-on-first-login of matching local accounts on local DBs
4) migration-on-first-login of non-matching local accounts on local DBs
5) renaming-on-first-login of non-matching local accounts on local DBs
6) provision for forced rename on local DBs
7) basic login for remote DBs
8) new account for remote DBs
9) migration for remote DBs
10) profit!
additional goodies:
11) secure login form
12) multiple-domain cookies to allow site-hopping