If looking to purchase ready-made systems:
Check out Rosies, Rack Systems & More in the breeders or suppliers section. They sell racks with Cambro polycarbonate food boxes that are low profile but roomy enough for adult display, and the boxes are crystal clear.
Another option, Precision Caging sells 24W x 12D x 8H cages now. You can stack a bunch up. They are super light in weight.
If building your own, I agree that Cambro polycarbonate boxes are great. If you have a Smart&Final near you, they sell them. You can also find them on Cambros website. Do a search for Cambro. The food pans are cool, like 10x21x4 high and clear.
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Mark 