Sintra seems to be the dominant market name for foam pvc in the US (like Sellotape) but there are a few other brands available in the rest of the world. This company in the UK stocks a good brand called Foamalux .
A quick google search for "pvc foam board" will give you some sources in your area.
from solarbotics.net - "Note that when you're shopping for PVC foam board, you need to make sure you are not getting Fome-Cor®, a.k.a. "foam core," which is much softer, and essentially just paper-faced styrofoam." Taht's the stuff I mentioned earlier.
A good guide to PVC foam boards -
Sintra -- the basics
