Hi jgart,
I am kind of new to Guix and I am struggling to find resources forlanguage specific recipes like you mentioned.
I started a project
https://lisp-spectrum.org/ where I try to document my struggles with the Lisp Ecosystemin general (Guix included).
For every Lisp, I try to include a guix manifest to make the instructions reproducible and I plan to add guides
on how to work with guix on many levels (OS, home and shell) for each language.
I'm only doing this project for Lisp dialects for now, but I can definitely see the benefit of having the same thing for other languages as well.