I use aquarium backgrounds for some of my rodent vivarium tanks. It's plastic and comes rolled up. I stick it on the outside of the tank using sticky tape around the edges. That way the rodent doesn't have access to it so it is safe and remains unchewed. I would never use it on the inside of a rodent tank, but then I would also never use a polystyrene reptile background inside a rodent tank either
You can see some of the background in this photo:
P1050838 by
vectishams, on Flickr
I got it from Amazon:
http://www.amazon.co.uk/gp/product/B...ilpage_o01_s00