It looks great, I would definetely subscribe but trusting a third-party with my IM data something I'm not comfortable with. Fundamentally, deploying a Matrix homeserver in the cloud is the same thing. Homeserver requires a public ip address or domain name, it's really hard to set up one at home.

I don't have enough information about Matrix protocol but, a raspberry pi image, or Dockerfile doesn't need IP or Domain, uses hosts file to trick the homeserver maybe, just supports bridges, would be perfect.