Create Arbitrage website for various retail and auction sites

We need someone to develop an arbitrage website that will allow our customers to order products from various retail stores and then auto list the items within various other websites. We would prefer that our website be built on a CMS, like wordpress or Joomla but, it can be stand alone. (An example of what we need is: priceyak.com. Once you have been selected as the winner we can provide access to [login to view URL] so that you can see the details of how it works. You can use a free trial in the mean time) For instance: Our customer finds a product on Amazon that they want to list in their eBay store (or auction). The software grabs all the relevant information from Amazon (Description, prices, pictures, variants, etc) and sends the data through their account on our website, which adds a markup, and then posts the product for sale via their eBay account. When the item sells on eBay our software needs to be able to automatically order the product from amazon and have the item shipped to the eBay buyers address. [login to view URL] uses a browser addon to grab the data, which is a possibility for this, well. We need to be able to add many retail shops that the system will be able to use for purchasing/shipping (amazon, walmart, costco, sam's club, newegg, best buy, etc.) as well as many selling outlets (amazon, eBay, etsy, rakuten, newegg, bonanza, ebid, seller website, etc.) The constructed website should be a centralized hub for our customers where they can view all relevant details of all their accounts, monitor sales, revenue and even accounting. We must also be able to handle billing of our customers from the admin portal of the site (or have the billing integrated with another software) we will also require a forum section for our users (preferably phpBB) which must be integrated with their account. Once completed we have full rights to ownership of the software. We will set the initial milestone to $300 and additional payments will be made in that same amount.