After seing those there's no way i'm displaying my lash up on here!!
I say be original and keep your eyes open for new things for them to climb in/on/up/under etc.
I keep adding to mine everytime i see something usefull on a skip...bits of pipe, plastic crates,ropes,boxes, bags,suitcases,etc.and add extra boxes all over the place.Then throw them away when worn out.
Mine live in a hutch made from old chest of drawers and play/eat/ poop in a hutch made from pallets and scraps of wood.
So far they haven't threatened to move out because i haven't spent enough money on materials...thank God!