You can create your own music store at Amazon.com easily

This service is called "affliate marketing". Every day, musics worth many million dollars are traded through affilitae marketing websites. Most muc selling website offer affiliate programs so anybody in the world can register as an affiliate start selling music from his or her website. I personally an affiliate with over 100 Internet-seelers. Similarly, I run my own affiliate program, so hundreds of affiliates from all over the world sell my e-products and earn commission, which is usually 20% to 50% for e-products.

And earn money as an affiliate from every sale (usually 6%). Many other e-malls offer a similar service. Specialized music portals do so as well. So, the idea is commercially great, but not new, unfortunately:-)