Crowdsourcing template or plugin

Hello,

For a new project I’m looking for a wordpress template or plugin which can manage a crowdsourcing activity.
I already foudn some good one but they all show the topic and my business would be more about private information which I don’t want to show to everybody…

I like the way of 99design for exemple but I am wonder what kind of base they use to do it…

I think the best way in this case is to use a plugin on wordpress but I am not sure if a good one exist…

Thanks in advanced for all of your advise about template or plugin.
Cheers