Decided to use the entire surface of the table the guinea pigs' current cage was on, which would give me a cage roughly 72"x30". This is built from wire shelving and metal braces screwed underneath and on the sides of the table to hold the shelves in place, and then zip tied into place. The inside is semi-translucent coroplast.

This picture was taken before all of their fleece bedding was finalized. That will happen more this week, but the actual cage part is done! The girls are so happy!