Very nice idea. You didn't exactly reinvent the wheel, scraping sites has been done before and leading straight into the Windows Live map leaves a few design implementations to be desired. Now, don't get me wrong here, i absolutely like how straight forward and "no-joke" your site is.
What would work in your advantage is if people are able to register for user accounts, save their searches and such - without having to log into eBay.
Overall, if you give this site a "front end/customized" interface and user accts with certain abilities, you're on the right track. right now: :tu:+1/2 out of 3
*and should the site + domain be for sale PM me with a price, i'm into cars, i'd have definite use for this*