Fabulous! I would actually be very surprised if no one else had already thought of this idea. I think it's all about executing well, because an opportunity certainly exists. I wish you all the best!
The restaurants giving out menu ingredients is quite idealistic though but possible using GroupOn-mentality (eg Everyone's doing it so I should too).
I work at a fine dining establishment right now for extra money, and I can tell you no matter how many other restaurants were doing it, our head chefs would be unwilling to share ingredients.
The challenges you outlined definitely put an idea like this in a "sink or swim" scenario.