Independent Plugin and/or Themes Update Notification

I think it would be great to have a simple notification system to alert users to updates of their independent themes and/or plugins. Like many other users of WordPress, I sometimes purchase themes and plugins from independent websites/developers. However, I’m not always up-to-date on when they are updated. I think it would be a GREAT idea if there was a place within wordpress.org where developers could register their themes and plugins (that were paid for by the user) with developer contact information, version information, and where to go to get the update. The system won’t have to include the files for the theme or plugin but just information letting the user know that there is an update available and where they can go to get the updated version of the theme or plugin.

(Basically, kind of like the WordPress.org plugin directory but without the files and is only for independently paid-versions of themes and plugins. Once a developer changes the version number of the theme or plugin then it would automatically put a notification alert in the users’ WordPress system letting them know that an update is available.)

Does anyone else think this would be a good idea/request?