As an added bonus, the provided patch searches for the user by either email address or uid, choosing intelligently which to use based on the presence of an '@' in the login. This would seem to resolve the blueprint you have on this project for the IIdentifier plugin. (By making it unnecessary.)
Alternatively, you could just lift the search code from here to create your IIdentifier plugin.
As an added bonus, the provided patch searches for the user by either email address or uid, choosing intelligently which to use based on the presence of an '@' in the login. This would seem to resolve the blueprint you have on this project for the IIdentifier plugin. (By making it unnecessary.)
Alternatively, you could just lift the search code from here to create your IIdentifier plugin.