Hi Bebop,
I'm not quite sure if I fully understand the thread, but have you possibly considered something like the yahoo groups, as a site for your mailing list members. I use one as a mailing list to keep members informed when I have a bear for sale.
Members could actually upload their own songs, styles , pads etc and there's an automatic notification system when a file's been uploaded to the site. All it would possibly require would be for the owner or moderator to delete some of the files if & when the files area got too full. Deleting could possibly be based on the length that the file as already been on site, so as to make way for new ones. Also keep any chit chat down to commenting on the specific songs so as not to detract from this forum.
best wishes
Rikki