As I searched a bit more I came across this box.
http://www.ecobox.com/Moving-Supplies/Moving-Boxes-Specialty-Boxes/Bike-Box
I like the size and it would work with iceIand Air I would still need something for the return flight.
But still might just go with the mattress bags again with lots of extra padding and then wrap the whole thing in strech wrap. By using tape and strech wrap it might hold up better to the TSA inspection.