Like all of the new units in Advance Wars Dual Strike, the Megatanks for all five armies look exactly the same, except the colours. I'll release the other three Megatanks (Green Earth, Blue Moon and Black Hole) once I've had a chance to build them so I can take some pictures. ;o)
Parts and instructions to build your own Yellow Comet and Orange Star papercraft Megatanks though are already available now from the Advance Wars section on my papercraft webpage: [link]
Have fun building!