Theme uploads via the admin UI

Hi,

I found this group post which petered out seemingly without any resolution:
http://groups.drupal.org/node/9552

One of my clients is interested in the idea of being able to upload themes via the admin UI so they can build their own themes and deploy them, safely, without the need for FTP/SSH access to the server (and the burden of knowledge such access requires).

Is there anything like this already? I'm thinking such a module could be Drupal 6.x contrib and simply provide:

• a permission for theme uploads
• a theme upload page where users can attach a gzip'ed theme archive (as presented by the Drupal.org theme packager) to be installed
• some PHP code to unpack and check the theme (make sure the .info file seems valid, etc.)
• after check, if it passes, copy it to sites/all/themes/uploaded

This way developers can exclude sites/all/themes/uploaded from their own version control systems and user-uploaded themes can be isolated.