Return 403 for authenticated users

We're trying to determine the best way to return 403 for authenticated users and 401 for unauthenticated users in services.runtime.inc when an access callback fails. We can change line 148 to the code below, but I'd prefer to come up with a solution where we could create a patch and not hack the services core. I know we need to take other authentication methods into consideration, but don't know enough about services to say what would be best. Maybe we could set a variable in the $endpoint->authentication loop and a failed access callback would check that variable or the $user->uid to confirm authentication. Thoughts?

  if (call_user_func_array($controller['access callback'], $access_arguments) != TRUE) {
    $response_code = $user->uid == 0 ? 401 : 403;
    return services_error(t('Access denied for user @user', array(
      '@user' => isset($user->name) ? $user->name : 'anonymous',
    )), $response_code);
  }