Since long-distance airliners seem to be the aircraft of choice for stowaways, Boeing and Airbus should install on all new widebodies, a hatch or door of some kind on the bottom of the fuse that stays open during taxi and takeoff and closes when the main gear go up. Inside the hatch would be a pressurized safe-haven for stowaways. Maybe no IFE. But maybe a Singapore Airlines first class cabin/seat/whatever they call it? Why not also have a chute through which the flight attendants deliver the leftover first class meals?
Obviously, it would save lives. Good publicity too. Think of it... BlahBlahBlah Airlines, the compassionate carrier.
Sure, it'd cost the airlines some money... but it'd save some poor guy from having to clean body parts off the main gear leg. It's probably bad publicity to pull up to the gate with the landing gear looking like that.
Last thing, all of the equipped airliners would have a decal on both sides of the plane... "Safe Haven".