What about going to the bathroom section and look at the soap holders or platforms that are plastic. You might just find a platform the you can hook in my making holes in the bin cage. Finding alternatives is a Good idea! You can also use plastic brown pot plant trays that are rectangular. If you look at my thread with the sand bath I made in the DIY section. It was so easy to cute etc. look for one that is square or rectangular. You can then put a hook on each side sand hook it through the bin. Will keep on wracking my brains. Oh...hang on...IKEA wooden rack
https://www.google.com/search?safe=s...s1A0BpAEjszZM:
You place it in the corner and cut out the bottom for burrowing.