Wizard to add OpenID to backend user
Google's OpenID provider gives out per-consumer-domain random OpenID URLs for users. This means that it is impossible to know what OpenID a Google user has before he tried to log in at least once.
To solve this problem, the backend user settings form should have a wizard to add an OpenID.
It opens a popup with a form to enter an OpenID. Then the OpenID auth process starts, and at the end the claimed_id is put into the backend user's OpenID url input field, and the popup closes itself.