I can't see anything but success for this idea.
I think it is important like you said to start with a small group of established names and labels to start with to build a quality image. I have to confess the first thing I thought was "great I can get my tunes on this" but I have to agree that it is important to build on quality not quantity. You dont want this turning into a free for all!

Great idea Mark I really hope this work sout respect for having the sack to put the ball in motion as it were!