I've been working on this solution and am currently in a closed beta. Will be opening up this/next week over time. http://hivereader.com I meet all your requirements but the cross platform. Once the web API's are locked (aka near the 1st) I am going to start cranking on the mobile app ASAP as well as a public facing api. I also have social but you don't need to use it. (no really, it's barely there).
Myspace needs to focus on what they are winning in. That is local bands and promotion for them. Almost every band has a Myspace and uses it for updates and music samples, etc... If they could rework their music section. They are already the leader in it and seem to be oblivious to it. Give indie bands a way to sell/distribute their music and promote it better on a hyperlocal scale and you win.