If you've ever seen the Red Alert video of the Mammoth Tank being put together, this is what we're going for. Part of the tank will appear out of no where like it normally would, but then the turret will be placed on top by the construction magnet. Then it will roll out of the War Factory.
The Single Player animation will go into more detail than this, with more of the actual tank being shown put together.
Go here for more details.