Yeah, lots to think about when building bunny cages.
What I ended up building was a wooden base with 6" sides and then glued lino to the inside and used metal corning stripping along the edge to prevent chewing. I love this design, and it clean so easy and the buns have not been able to destroy it at all.
Sorry about the green colour in this picture, my camera was dieing, but it does give you a good idea of what I did:
And another one:
One one with bunnies in it:
If you do use lino, make sure there are no seams along the bottom. They can and will start pulling it up from the seams. I only have seams in the corners where the sides meet the bottom, and I use a small bead of silicon to seal them. I have not had any issues with it so far.
-Dawn