I'm seeking desperately for a plugin that:
- assigns a category to a site
- allows to display/order the list of sites organized by category (even if it is not the default listing /wp-admin/network/sites.php )
But yours is up to date and have the potential for it.
And.... there's nothing* of the sort in the whole plugins directory (free or premium), I thought maybe you could accept the chalenge...
* i can guarantee i did a in depth search ;o)