I would like to make more levels in my rat cage/cover the wire floors. Besides linoleum, what other materials?

I use fleece to cover my cage. It won't catch your rats nails and it tends to wick away any moisture and is easy to spot poops on, making it easier to put them in your rats litter box. It helps them to realize where to go to the bathroom. You can buy cheap fleece at joann fabrics or any other fabric store. Try visiting goosemoose.com, click on Rats Rule on the left hand column, then click on Home Squeak Home, If you click on the Critter Nation Cage post you will see a lot of photos of fleece lined cages. It might help you get some ideas. Good luck!