Plugin for contest type site

Hello!

I am looking for a plugin that can help me with the following. I understand that there may be a need for some modification.

I am looking to build a site for companies to submit a request for graphic design (logo, banner, flyer, etc). Within these requests, designers would be able to submit concepts and the seller could choose their design submission. There would be a reward already specified that would go to the winning designer. All “contests” could have a specified end date.

I know there are a couple websites already like this, but not sure if they are using a WordPress platform.

Any ideas would be greatly appreciated. Even a plugin that could get me close and then hire for some mods.

Thank you!