Good question. I was always afraid of my video tapes getting messed up that i take while skiing and my camera cards getting messed but that has never happened. Ill take a look around and see what i can find for ya.
It is true that Lead is used to prevent the penetration of x-rays, however, finding a lead bag will be harder nowadays since lead is toxic and its sue is frowned upon.
It is ok to allow cell phones and laptops to go through an x-ray machine at the airport. It will not erase your things. X-rays are actually fairly harmless except for prolonged exposier to humans.