Generalizing user auto-creation support

Right now, supports auto-creation of users if you configure the NativeUserProvider (which is actually just the default user provider in disguise). I am interested in generalizing this auto-creation support to cover other cases where a user might be able to authenticate but has no user record–for example, if you’‘ve configured GSSAPI authentication, but don’'t want to use an external LDAP or JDBC user database. Obviously, this would be conditional on a property.

The generalized code would have to live in (or be invoked from) and, it looks like.

Does this sound like a reasonable feature?