Custom Data at the Playlist/Syndication level?

Hello, we’re trying to get richer metadata at a playlist level to create feeds that have more information. Is there anyway we can add additional info to playlists outside of tags,description and title? Currently, the only workaround I can think of is using XSLT and parsing the first item in the playlist with a field that includes that channel information, but that requires putting it into every item in that playlist- not an idea solution. I see that Custom Schemas can be applied to multiple types of entities, but currently just Entries and Categories.