We developed a change to the core today that allows users to either share themes and have access to all core users themes or make there theme private. This is extremely useful to give share users the ability to have many options of nice themes that have been tested out on other websites. This also grants users the ability to stop sharing themes and create their own custom themes they do not want shared with the group.
Please note we already had begun individualizing domains within WordPress by separating the uploads into separate folders and now, for only $10 a year, you can have full FTP access to your private themes, uploads and optionally a private plugins directory also.
Right now the configuration file changes are effecting all domains, which has caused us some headache. We know this can be frustrating as it causes 10-15 second downtime’s on your sites. We are currently working to make configuration files for each domain so that configuration changes used to customize a domain do not affect all users. We expect to have this up by sometime in September.