Great plugin! It's 95% of what we need. Any chance you'd accept a patch to only allow access to a site to those who are users of the site?
Our use is that we want to be able to create "private" websites on our multisite network, where access is managed by whether you're a user of the site or not. The plugin currently redirects logged-out users to the login page, but logged-in users who are not a member of the site can easily access the content.
Thanks for the consideration,