@ricmac I don't, actually. I mostly wanted to get your take on it!
The best I can imagine is using something like https://write.as/ or https://wordpress.com/ with the ActivityPub extension, and making followers-only posts.
You could have follower approval on, and have a mechanism like a Patreon, Ko-Fi, or Paypal to let people subscribe. With existing technology, I think you'd have to collate these by hand -- asking the subscriber to include their fediverse handle in comments.