Here is another small plugin, WP Site Suspended. It is simply a simple way to alter the appearance and message that WordPress shows if you archive a site in MultiSite.
We use this at work for various reasons, non-paying clients, etc. Needed to make it branded and look a tad better with more information, this is the result. It will work in conjunction with my other plugin Simple Login Customizer so that any customizations done to the login form will be brought in here as well, keeps it nice and uniform methinks.