Here's the Python version I've been using: https://gist.github.com/dextercd/3bd65c1e32635b9e7bebf287b52...

Another issue I just ran into is that a colon separated value for ExecSearchPath doesn't work in systemd-run/-p. You have to specify each path as a separate -p argument.

There are some minor annoyances like that, but it's not too hard to work around.