will web developers work for free?

[Denver]

So I've had this idea for a while now, have compiled a small team and have investors interested. VCs are wiling to invest 2 million dollars in the idea but for 80% control of the company with clawback options. I have since found that if i can create a working model here in denver before getting investors involved, i can likely keep the controlling share of my company.

Now, I need to find a web developer or two, but since our team (4 members) all have full time jobs and are moon-lighting the project, we were hoping to find a developer to do the same. Work for free in exchange for a share in the company and a lead job in structuring our future development team as we grow.

Isnt this how facebook started? are developers willing to do this for a chance for a bigger payoff and a secure job in the future or is it asking too much?
Ive posted job requests on sites like craigslist but get back mostly replys from web development teams willing to bid on the project (even after stating what we are looking for).

Is there a better way to go about this? your advice is greatly appreciated.