I've now written up all the progress in our MediaGoblin Guix channel README:
https://git.sr.ht/~mediagoblin/mediagoblin-guix/tree/master/item/README.md In short MediaGoblin can be installed as a Guix package with no external dependencies or Python virtualenvs. After some slightly clumsy static files configuration the web interface runs successfully based on an SQLite database. The Celery backend run successfully. Images and video can be uploaded and viewed successfully. Video plays via the stock browser player but doesn't allow selection of video quality. Audio is broken pending merge of updated libsndfile from Guix's "core-updates" branch. To try it out, follow the instructions in "Install via load-path", followed by "Run MediaGoblin" from the README mentioned above. Regards, Ben