I'm sure the majority has figured this out, but you can actually move items into the bathroom of the Silver Rush (by lifting them, not putting them into your inventory) and then crouching to be hidden and steal them. Now be careful because sometimes you can be detected through the wall and sometimes the values don't add up, if you have to reload. Sometimes the plasma caster will be 6995 and sometimes it will be 395. It's some sort of glitch that I don't quite understand. But nonetheless you can easily make plenty of bank if you play your cards right. Everything 'stolen' from Silver Rush is considered legally yours if you re-drop it. Regardless, it's not considered a crime to kill the Van Graffs so if you have the muscle, you can just take everything for free without sneaking.