Muve is the model

From the marketing brochure page at mycricket.com/muve-music:

Muve Music from Cricket is a game changer for everyone. By tightly integrating the music service into the handset and the billing plan everyone in the value chain benefits and consumers have a complete music service where the phone is the hub not the PC.

And Muve is doing very well as a business. My memory is that the subscriber numbers are in the hundreds of thousands, which puts it well ahead of Rdio or MOG.