I haven’t found anything - but I might have missed it:
Is there support for tagging classical music? Classical music has other requirements for tags (see for example http://www.thewelltemperedcomputer.com/TG/2_Classical.html ). Is there a plugin or configuration which can be used for tagging classical music?
Many people use beets to tag their classical music! And MusicBrainz has a lot of data about classical music. Can you be a little more specific about what you wish beets did differently from what it currently does?
Something that seems quite similar to the link you showed is the
parentwork plugin, maybe you want to check it out?