Heck yes, I would be very very interested in seeing what GarageBand has really done to make music accessible to the masses....as well as to the talented souls out there who may have been languishing due to lack of studio funds! My mind keeps going back to how little equipment it took Trent Reznor to get Nine Inch Nails started....
A couple questions: I'm guessing you wouldn't be licensing FairPlay, so the music would be without any DRM? No authorizations, restrictions, etc?
Would the format still be AAC? If so, what sample rate?
Also, would it be a requirement of the site that any music up for sale must have been made on GarageBand? Or would you allow stuff started in GB, and completed in other software, or just any song that GB has touched somewhere during its production?
But yes, go for it! definitely!
GoDaddy reports that indieMS.com is available, if you're going to flirt with angering Apple's legal department.