Consumer 2 Consumer ECOMMERCE site Flexible Budget

Need a fully functional ecommerce website. Can be built upon an already existing system like osCommerce. Graphic Design already there needs integration with development Signature of NDA required Features: Consumer to Consumer ecommerce solution. User driven ecommerce website Similar to Amazon, ebay but not as complex User ability to create a product and post it online User ability to search for products and purchase them Products will be online based therefore we need users to be able to download product after purchase. More than one user to purchase the product User profiles Users can post a request for a product Payment Gateway integration like Google checkout or Paypal Service Charge deducted from final sale between users to Website owner