I looked at the project in Somalia. I think the idea of a whole village is good, yet I extremely doubt the idea of them paying 20 dollars per month for charcoal.
http://www.sunfirecooking.com/
The cost of around 200 US is unfeasible and not sustainable.
I do not see this as a solution.
I was interested though in the Aluminum Tape on the parabolic shape. I see no reason why many person could not make one out of clay with a mold.
In the end people sit around in the morning and at night mostly cooking over a wood fire so they can either sell the food, or eat.
I am now getting more thoughtful, how can a person cook when they need to cook and not when the sun is shining.
I can generate electricity I believe easily, how do I store it and not have a ton of weight?
I tend to think they would like an electric system they could use at any time of the day or night.
I do not see a clear path to feasible or sustainable solar cooking.