A wild idea, but hang with me here.

You've seen Vinay Gupta's Hexayurts....basically these easy-structure-homes are built of simple tiles of materials available locally. A home in his book does not need to cost more than $200. http://howtolivewiki.com/

Your trash tile idea could be a real way for kids to turn trash into more stable structures and homes. Tiles become panels of a home, reinforced on the outside with layers of artified plastics and random bits found in the dump. These structures would beautify while also offering protection from weather.

12 kids could make a structure in a day, easy. Groups could sponsor materials sent as part of their PeaceTile partnership swaps to get the structures built and fundraise for that in their own peacetile projects around the world.