Maybe I misunderstood? As I read the first post we basically have a situation where a community will collaboratively define the product. i.e. this mug is cool, this other one isn't. and all that content eventually leads to a phycial product, a cool mug, which would be a naode of type, product and could be placed in the cart by embedding cartlinks within the content pages that helped to define it originally.

That was the scenario I was reacting to. In the downloaded file case, I need to give it some more thought.