I bought the mesh cubes at Linens n Things. I had bought 1 pack (17 panels) about a month ago, and we just built the cage and found that we needed more. Not all of the Linens n Things had these cubes...I think they are mostly out during Back To School promotions. They are great because when the piggies stampede and run like crazy, the bedding doesn't fly out onto the floor.
I have one mother piggy and 3 babies living in there now. They really have so much fun with all of the space they have to run. I am glad that I found this website, or I would have never known about making a cage like this.