How best to deal with users whose logins change

Nearly every week we have one or more users who's login changes. Sometimes a user changes his name. Sometimes it is due to the fact that our logins include a department number - a user changes departments and her login changes.

In the past with SP 2007, we did not take a specific action for a user. The changed login appeared in Active Directory. The user logged in. Their mysite data was there albeit with a URL that contained the old login. Also, their permissions remained, etc.

In SP 2010, I am not certain what is going on. We have had one user who contacted us because their mysite data was missing.

I tried the powershell move-spuser command, but it gave me error messages about the old login not being found.

I also tried the stsadm -o migrateuser with similar results.

The ideal situation would be that when the Active Directory entry changed the user's mysite URL also changed automatically to reflect the new login.

That seems unlikely to be available.

So, what steps can be taken by someone with farm admin rights to make certain that a user whose login has changed still gets to their mysite after the change has taken place?

Thank you.