Not sure if this will remain in stock, but Gamma has Coroplast (polycarbonaat kanaalplaat, 6mm)

I recently used it for a 2x4 c&c cage. I found that most coroplast is 98cm wide, this one is 105cm. It allowed me to have slightly higher sides.

(It is semi see-through, so you can see everything you put into it. I have a 5cm layer of woodpellets on the bottom, which is clearly visible.)