I built BuyMyFile (http://bmf.cm). BMF is a file marketplace that rewards buyers with discounts for referring sales. Please let me know if you find this service useful so I can keep working on it. Thanks patio11 for feedback on this.
I haven't tried it out just yet, but you should certainly keep working on it. Great idea!
The site is still raw but I decided to put it up to get feedback. It's a file marketplace mixed with a referral system. I think people should be rewarded for sharing.