Well, you can start with this from Outrider;
http://www.joedios.com/dioramas/sho....php?i=5126&c=7
I would say make a building like that, and using model wood from Michaels, build a partial wood frame inside. Then tear some chunks or entire walls off and on the edges burn them with a lighter or blowtorch.
I know..I Know....

I'm gonna go to Michaels today and try to grab some spare wood. I'll see If I can slap something together!
Or you can check EBay (or maybe a TRU or KayBee tosy) for the 21st Century building sets! They had a ruined farmhouse, hayloft, city fountain and bombed out building. They are WWII sets, but they work with the joes!
Hope that helped....