ONLINE MARKETPLACE

Online marketplace needed. We need a site that allows vendors to set up a "shop" featuring their products/services. The products will all be digital. when a customer buys from them we get a percentage of the sale. maybe similar to Elance's buy now service or ebay/yahoo shops. Each vendor will have his/her own shop they can add thier own logo to as well as a private message board ect. They will need to be able to upload portfolio items as well as have a workspace for exchanging ideas with customers. This site will be similar to a freelance site exept people will not post jobs, they will browse portfolios to find the style thats right for them. Customers do not have to signup or create an account to shop. Vendors will pay a small monthly fee to be included on the site. (There may be a couple of different subscription [login to view URL] can pay more to be "featured" ect.) as well as a percentage of each transaction. Customers can rate/review vendors. Should run on Paypal for payments as well as feature an Escrow service. Needs robust Admin for banner ads ect. NO DESIGN IS NEEDED JUST THE CODING/BACKEND As far as I know this shouldn't be to difficult. Im not in a rush, but I would like CONSTANT communication on progress. I pay ONLY with PAYPAL. Please show us examples of similar sites you have done. I will need to see a working demo if possible. I don't care where you are in the world, but please SPEAK & understand ENGLISH. This will also lead to ongoing support on the site as well. I've tried to lay it out the best I can here, let me know if you have questions.