Reverse auction or similar? Plugin/Theme

Hi there,

I’m looking for a plugin or theme that will allow me to do the following (pretty much like Elance).

I need one set of users to be able to post a project, and award the project to the winning bidder.

I need the other set of users to be able to upload files, apply them to the project, or add them to a library.

Once uploaded, The admin should be able to view/edit/approve all details.

Anyone know of anything similar? Any hacks/modifications I could apply to anything that’s out there at the moment?

Thanks

Chris