There is a shortcut key for fast user switching: ctrl+alt+>. Currently this works only after another user is logged on by clicking on 'sign in another user ...' and its password is typed.

I think it's convenient to immediately open a logon screen as if 'sign in another user ...' is clicked when ctrl+alt+> is typed but no additional users are currently signed in.

Additionally, when cycling through users, it would be nice to pop up the logon screen whenever the index hits the last slot +1.