I cam across a new product the other day: Paperstone.
We were using a piece for a museum project and we cnc text onto the surface of the product.
The material is very heavy and hard (multiple bits were used to cut the engraved text), and oil / water affected the product - though it is to be used as a counter top surface.
It's interesting that its 100% recycled - but at a rumored 800 a sheet, I doubt I will see it for theatrical purposes. Regardless - I thought it was worth a mention as it is different than what we normally get to play with.