This plugin works in WPMU http://premium.wpmudev.org/project/e-commerce/ We need to have a standard set of products (that resides on a subsite managed by the super admin) which will span globally through the entire multi-site network on every subsite. And then use the following plugin to set which subsite can turn off the standard products if they want to: http://premium.wpmudev.org/project/pro-sites/ Please let me know if you are interested in this project. Thanks!