Sam,
I myself own a forum dedicated to online trading, so I am really concerned about your project. I myself thought about creating such a site. I would love to take it in charge and extend it's use by adding features like voting to backup a bad member (which could eventually automate the deletion of honest members (ie. X reports = deleted)). If you really want this more open source minded, I'd advise you to literally remove registrations and allow everyone to add additional information about bad members rather than editing the actual one (to avoid abuses).
Anyways, unfortunately I can't accept any jobs before Christmas vacations, in a month, but if you could wait until then, I'd be glad to work on this.