I like the styrofoam wall idea, it makes all of your basic construction materials compatible.
cmon guys and gals, I can take some critic, really don't be shy.
What is the size? what are you using? is this for a multiple cage setup? The tiny pictures make it really hard to figure things out. For something like this it would be nice to see step by step instructions with each phase. This way if someone wanted to replicate this, they would have a great referral to here.