permissions

I posted this in the main drupal forum but I thought it would be better to repost it here since the right people can see it easier(and hopefully answer):
http://drupal.org/node/69399

Can anyone help clarify for me how this system would work? I'm basically looking to make a site where I control the main audio content but also allow users to upload remixes of that music with size restrictions. I tried a goofy thing where I took the Audio module and I renamed it and it's sister files to audio_user and uploaded it but Drupal is too smart to allow a duplicate module to sit next to the original right.