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?