Develop barter website in Python hosted on Google AppEngine

You MUST have extensive Python experience for this project. Please do not bid if you are not highly proficient in Python. We prefer that you also have AppEngine experience but we will consider bids from developers who can get up to speed quickly. This project is for the development of a barter website. Users can list items they want to give away in exchange for other items they find on the site. From a functionality perspective the website is highly similar to eBay for example, but of course much simpler in implementation. A separate matching engine has already been developed in Python and is hosted on AppEngine. You will be responsible for developing the user-facing front end of the system, and must interface with the matching engine. Your subsystem will periodically send new listings and user selections to the matching engine (via AppEngine protocols such as Task Queue). It will also periodically receive possible matches from the matching engine and notify users about the match. Since the matching engine is already hosted on AppEngine we prefer to also host the front end there, and develop it in Python using a framework such as Django (we are open to other suggestions). The front end must be architected in a way that will allow it to take advantage of AppEngine scaling capabilities.