for a 3 stacked cage? What would be the best way for doors? A track with glass... but gaps?? What about heading it? I don't really know what these Walmart bookcases are made of. But there's one like this for $16 at my local store.
29.63" W x 11.5" D x 43.5" H
May be better with one of the solid wood ones....
Surely something cool could be done though