As you progress the Watchtower storyline, there will be contraband cases on Stardock. What's nice about them is that when you have to turn in those items for improvements they can be automatically pulled from the crate so you don't have to keep grabbing them back out to have them to people.
I've seen one in Gren's workshop, one next to B.A.B.S., and one in the Clinic that eventually opens. I keep wanting to stash harvested organs in that one.
