Peer to Peer Ecommerce theme similar to the way TextBroker.com works

I looked at the available themes and plugins on WPMU but I couldn't tell if those solutions answered my question. I'm looking for a peer to peer ecommerce solution where buyers and sellers can work with each other and a percentage of the transaction is taken out as a service fee.

Something very similar to the way TextBroker.com works - people in need of content can browse profiles and submit article requests, writers respond and a portion of the transaction goes to TextBroker. Are there any out-of-the-box solutions that can handle something remotely close to that?

Thanks!
Joe