That sure would be nice. Remembering all my usernames and passwords on blogger, orkut, gmail, etc is getting out of hand. Of course, integrating all of the accounts is going to be fun as well, because dactyl on blogger might not be the same guy as dactyl on gmail, etc. No real good solution for that other than people losing their log in names.
Of course, gmail is the only place so far where the login name really matters. Orkut and Blogger don't really have any association between username and your online identity. That would make it easier to integrate.