After buying the Earth Defense HQ (set 7066), I was hooked on the Alien Conquest theme. However, I was disappointed by how few ADU vehicles were in the line so I set about to make one of my own.
The MPT (Multi-Purpose Transport) is a six-wheeled vehicle that can carry a variety of swapable payload modules for different missions. There is room in the cabin for an ADU driver and clips on either side for weapons/accesories. In the first few photos, the MPT is equipped with a gun and missile turret. The turret can both rotate and elevate and the missiles are removable. When removed from the MPT, the turret is free-standing and can be operated by a minifigure.
Another module for the MPT is a radar/scanning dish. Like the gun/missile turret, the dish can also rotate and elevate and is free standing when not attached to the vehicle.
Another small module is designed to house and transport any prisoner pods captured from the aliens. The pod can be taken to a safe area where medical personnel can free the captive. The pod pictured is the one that comes with the Tripod Invader (set 7051).
Lastly, a group shot of the MPT with all my ADU vehicles. I modified a second Alien Defender (set 7050) with a flick-fire missile rack instead of the gun turret. Next to the MPT is another of my Alien Conquest MOCs, the ADU Strike Cycle.
I really like your addition to the line of vehicles in the theme. The cool thing about this theme is that it's pretty open and you can create some cool stuff to go along with it. I just made a group of elite ADU troopers that I will be posting soon.