For Site Templates, add status for maintenance mode

Often we need to remove a site template from marketplace temporarily in order to carry out maintenance. This downtime is necessary so that the site is not changed during a site copy.
However, from a user's point of view, the module would just disappear, which would cause confusion.
It would be nice if the site could appear to users still while under maintenance, so we could show the "while unavailable to install" button with text explaining the maintenance, or a status which shows an automatic maintenance message?