Bump up for this. We have a requirement for this. CAMRA often sends out email communication to our 170k+ members. Many of the topics may involve further follow-up and debate so my suggestion is to include a link to our new Discourse forums but we don’t want them visible until the email has gone out. Chicken and egg in that you can’t get the link until you’ve created the topic. Creating it in a hidden category means that only certain people can make use of the feature so that’s a workaround at best at the moment.
So scheduling the post would be useful but we’d also need a way of removing the schedule thus manually releasing it.