Presumably to twin the A380 would also require a great deal of wing structure redesign, since there would be a great deal of redundant structure outboard of the engines. I wonder what the CG issues would be, As well as fiddling with the undercarriage to maintain nacelle clearance? The 330 / 340 wing was designed as a dual purpose item, but I for one have not heard any such suggestions being made about the 380 wing.