If I do it I’ll start with a UI that doesn’t involve a player. It seems like the player part might be difficult and I have no experience with that. Right now it’s just a dream scenario anyway.
I’d be interested in this as well. I think, instead of reinventing the wheel by making a GUI interface from scratch, it might make more sense in the beginning to create a plugin for an existing GUI music library application.
Another option would be to update the bpd interface to support the latest MPD protocol in order to be more compatible with MPD clients (IIRC, ncmpcpp and others require 0.17 these days).
I’ve actually been working on exactly this! My work in progress PR #3214 is at the stage where clients like ncmpcpp more or less work. There are still some compatibility issues to iron out, but I’m making incremental progress. If you’re able to test out some other clients and report back on how things break, that would be very helpful.
There is a “music player” if you will, that supports beets. It’s called Ampache - http://ampache.org. It’s not a typical music player in that it’s more of a media streaming server, with a web client, and compatibility with subsonic, Plex, UPnP, DAAP, and WebDAV.
So if you’re interested in running a web server for for this, it is possible. Just to add though, I did have issues for getting it working, though others do so results may vary. It isn’t too much if a bother for me anyway, since I just point Ampache at my beets music library anyway, and use a script to update both.