I am trying to set up a marketplace to sell photographs to be used as Book Covers.  To that end I am selling a digital product, however I need it to be an inventory of only 1, not 1 per customer.  
Once someone purchases a photograph, I don't want it to be avalibale to anyone else.  The only option for this I can see is the 1 download per customer, which I am afraid would allow more than one person to purchase the same product.  
Is this possible?