I really don't see JAL odering the A380. First of all, they are the largest 747 customer in the world. In addtition, the domestic 747 seats 500+ and ANA has a much stronger domestic grip. While United is a possiblity, their 747's are used primarily on Asian routes with some of them being switched to smaller 777's. It will be interesting to see if United would be willing to order a few. I really can't see American ordering any.
GOOFY, i don't think United and American will order the A380. I think United has been phasing out some 744s so I dont think they will buy the A380. American doesn't need a plane bigger than the 777 just like Flight152 stated. British Airways may get the A380 to relieve congestion at LHR.