Dan Moren has posted his wish that iCloud accounts could double as Mac account logins. I think it’s just a matter of time, and I’d be very much in favour. Given the deep interlocking of the iCloud account into the AppStore, it seems that almost all of the authentication side is already in place. One potential problem – apps are not portable in the cloud (yet).
Update Creating A new account in your cemetery, the system offers to let you use your iCloud login as a password. Interesting!