That seems like a great idea, especially if the default is set to not show the unofficial versions. This would be a gain for users of Drupal.org (more reliable downloads) and it would likely encourage better practices among developers without forcing anyone. Devs can opt-in or not, but I'm guessing that most developers would indeed like to have their modules listed by default.
I'll put my effort where my mouth is and help get this done, if anyone is willing to take me up on it. :-)
- Caleb