I would like to suggest adding the position of "Bandmaster" to the available Artist relationships. This is different to that of a Conductor, as some brass bands have both a Conductor and a Bandmaster, and are credited as such.
Is it alike concertmaster but for band? That is, bandmaster is one of the band members? Then, what about adding a “lead” attribute to the member of band relationship instead?
Edit: I moved your topic to MusicBrainz / Style subcategory.
For future reference, the "proper" way to request a new relationship is via the Style proposal procedure:https://musicbrainz.org/doc/Proposals#Request
@reosarevok: That would be nice to have it explained on About the Style category as well.