Yay, I wish we had the chance to have a slab party as a family - I was really dissapointed we couldn't due to distance.
Sounds like you're estate is going to be built very quickly which is great.
I think what you're looking for is a company who makes 'wall murals'?
This one does if you go to the section 'design it yourself' https://www.thewallstickercompany.com.a ... fullSite=1.
There should be a place in Perth that does this but I've always bought online. We are having a wallpaper feature wall in our kids rooms too. I can't wait to see the wallpaper we've chosen up on the wall on person!