For those who were involved with metadata conversations via Opencast a while back, this may be of interest. The format, aims, and goals look to be slightly similar, though focused on a larger set of "educational resources":
Looks like the call for participation has passed… I unfortunately do not know anyone on the current working group. Is there still a metadata interest within the Matterhorn project? If so, it might be an effort to sync up with at some point.