So I also just completed building sshbox an SSH daemon/server that lets you run an arbitrary command when a user session is logged in and authorized. For example running box run alpine /bin/sh as the command “boxes” (as the README states) users into a container. There are two ways to authorized users, via an authorized_keys file or via Github. Just release v0.0.1 and am pretty happy with it! 🎉 Let me know if anyone would like to test it!