As a programmer I'm not going to to in 50/50 with you on a site that would take a ton of work to build. I think your best bet is just to go ahead and outsource the work with an NDA. If you are really concerned, it might be worth it to find a local development company. It will probably be more expensive but you will have more control over what they do with your project and ensuring that they abide by the NDA contract.