And here is another discussion:

--8<---------------cut here---------------start------------->8---
Re: Invoking user shepherd; Was: Re: Defining *user* services in Guix:
https://lists.gnu.org/archive/html/guix-devel/2017-06/msg00132.html
--8<---------------cut here---------------end--------------->8---

> This would be awesome! How could we help you to make this happen?

First, brainstorm! :)  There are quite a few points that are still unanswered.

Second, gather the code we already have.  In my understanding, quite a few
people have worked on it already.

-- 
Pierre Neidhardt
https://ambrevar.xyz/