Not too long ago we were at a BDSM craft fair in Hamilton, ON. There was a guy displaying some chain mail creations and one of them was a hanging cage made from chain. It was beautifully put together and obviously secure. The big bonus of course is that when you take it down, it flattens to the round wood floor and would easily slide under a bed. As soon as I read this thread I was trying to remember what the guy's name was and finally figured it out today.

His site is found at http://www.chainmailguy.com/naughty2.htm