Having very swiftly outgrown their plastic indoor cage, my three "babies" are in a makeshift cage made out of the top of the indoor cage, with an attached run made out of IKEA shoe shelves. They love their extra room, so I've ordered them the bits to make a 2 storey C&C palace :o
I've also got some fleece for bedding and they already have a large plastic hay tray. They are definately going to be indoor piggies, with some grass time when this bloody rain lets up and the weather gets warmer. DH is less than impressed that they are taking up a considerable amount of floor space, but he loves them really.