The French band Phoenix did something like that. They had on their site where you could download the tracks for each song. I think it averaged ~100MB/song becau

The French band Phoenix did something like that. They had on their site where you could download the tracks for each song. I think it averaged ~100MB/song because you had an MP3 file for each guitar/keyboard/vocal track. I didn't have a lot of experience with multitrack mixing at that point, but I was engrossed for hours in Garageband mixing things up.