Hey Gregor - I saw where you were struggling with setting file ownership on individual sites at
https://webinoly.com/support/975/chown-problem
I'm curious to know if you had a working setup that allowed a user to be restricted to a particular website/document root while also allowing WP uploads to function properly?
I was able to create users and restrict their SFTP root, but that required changing permissions on the folders that (at least in my experimentation so far) prevents WP from being able to upload files via the normal web interface. I posted more details here:
https://webinoly.com/support/1305/creating-additional-sftp-users-with-access-specific-sites
Any insight you can provide on how permissions need to be configured would be much appreciated :D