How can change RealName / User account link destination in D7
Did you try hook_username_alter in Drupal 7.


  Alter the username that is displayed for a user.
  
  Called by format_username() to allow modules to alter the username
  that's displayed. Can be used to ensure user privacy in situations
  where $account->name is too revealing.


I've used this occassionally, but I find sometimes there are instances where I felt it should have been called/used already and then wasn't (the Webform module submission report tables come to mind ...)