There is no standard cage made that will do for an ackie. What you need to do is modify a 4x2 stock tank. The tank will set you back $100.00 and that's before you manufacture a top, run the lights etc.
Ackies dig and anything that can fall on them will. When you are running 2' of substrate, it is unlikely that your stack will reach all the way to the bottom. You will find that they tunnel and dig under most structures. Anything made of stone or brick will fall on them and injure them. Build a retes stack out of wood and don't worry about coming home to an ackie pancake.
I use straight DG from a local supplier.