Here's my idea, feel free to take it since i doubt ill get around to working on it.
so my idea for the Civilian Mecha was to make a pallet jack robot for a space age Wal-Mart! make it with pallet jacks/forklifts for arms showing it in action lifting a pallet full of water and air tanks for those busy space travellers and add an extra touch of in the background have Wallys world 3000 with space ships in the parking lot. (if you ever seen Spaceballs the diner floating in space.)
lol so thats my idea, like i said please feel free to take it since i dont have the supplies or time to make it.