The Slide/Climbing Board is made using Solid Pine Furniture Board (aka Timberboard). You should be able to pick this up easily in any DIY Store or Timber Merchant.
Our little one certainly loves it, really great to see how his play changing as he gets older and more capable. You can print it on any size paper you like, so long as you set the scale to 1:1. Though it is optimised for A4.
