Bidding Software

I am looking for someone who has worked and developed bidding software in past. I am planning to launch a bidding website specific to one sector but targeting world-wide market. I will disclose the market to short listed candidate firms. The concept is very much similar to Freelancer but it is not software related business.. So, when a person has a specific need or multiple needs(from that specific market), s/he will place his request on the portal. All vendors who are online, or have signed up for providing services or registered on the website will be immediately notified through messages to bid against that service within the given time. The portal will accept the payment, and will pay to the provider after deducting commission or if the user wants to make the payment directly to vendor at time of receiving service, the time of commission will be higher. Also, the administrator should have a function to invite different vendors on the website to join it. The creative part/ layout of website is very important. So, there will be user interface, vendors interface, manager interface (given region wise), administrator, banner/ advertisement management, etc etc. Those who are interested please share your work especially the creative work.