If someone has over $100,000 in undeclared cash stored in a safe deposit box in China, how could they move it out of the country without problems?

You don't physically have to transfer the bills out. Barring buying any form of a paper instrument like a Bond (which is a bearer certificate), the easiest would be to arrange a Hawala - or its equivalent. Hong Kong is full of this. You provide an account number worldwide and the amount would be transferred there. If you must take money out, I doubt getting it out of China will pose much of a problem. You can always distribute it. Its the other end you need to be worried about (Customs). With so much cash on you, in person, chances are you'd be a dead giveaway by your looks and nervousness.

Look for an option to turn the money into a convertible bearer bond. A single piece of paper worth US$ 100,000 is easier than carrying a 1,000 notes.

The best arrangement for you would be to turn that money white, using a government sanctioned (legal) scheme.