How about adding a glass box that can be locked. This would allow you to see an item that is in the box while it is locked. This way someone could open the box and look at the item but not be able to take the item. This would allow for example: at an auction everyone could look at the item but only the person with the right key could take the item. Maybe the box could be made so when the keyholder places an item in the box no one can pick it up. If the keyholder clicks an item in the box it jumps into their pack. If the box is not locked down then an axe could be used to smash the box.