No one would really do this for free alone. Maybe not for cash, but I am sure having it in their portfolio would be more than worth it. Being part of a 40 person team, not so much.

It is easier to collaborate on code than design, which is most important as I am sure the code would be trivial, or at least not useful to reuse. 40 designers would seem like a huge mess to me, and 40 programmers would seem a bit overkill.

If I were him I would choose the best of the 40 and pay them a fair rate.

+1 “Getting people and organizations in sync is the project of our times.” – Seth Godin in “Organizing the Unorganized” This idea's about the right thing to do then.

I couldn't agree more, I hope this collaboration brings something really cool