Leafing through a sign magazine during lunch today I came across a product that made me wonder if it would be practical for scenery. Its High Density Urethane. Its works like wood, but is much more durable. And it comes in sheets up to 20" thick! It seemed like it could be a good alternative to foam when durable carved surfaces are needed. It also seemed like it would be a great alternative for outdoor theatre.
You can look at the FAQ at: