I like this idea, but maybe a house on wheels powered by a coal powered engine. It might also have wheel upgrades and engine upgrades. The body of the house/car is able to be built off of and it'll effect speed for how many blocks are on it, but can be fixed by a engine upgrade.
One thing I don't get is the xbox suggestions forums, it's just filled with the standard suggestions but worse, and alot of things that they would never do exclusive.
Anyways, it's an interesting idea, but this game is SOMEWHAT realistic. I understand some rich idiot has a house that is actually 10 unfolding RV's, but it isnt really what they're going to do. Imagine trying to move your RL home right now. And I don't think that they would make something so simple so easy. Want to move your house? GO BUILD IT ELSEWHERE
As cool as it would be to just have the ability to build your own mobile transports (like a full blown pirate ship or a zeppelin or even some sort of large land transport) something like Archimedes Ship MOD is not likely to ever be implemented into vanilla.
However, IF Commands and Command Blocks ever get implemented on the console, the copy and paste feature is a definite possibility.
But I think that 4J will want to design a game controller friendly Command User Interface first... something with menus and such to avoid typing in most cases... maybe have a Type command override, for players who have keyboards and find the Game Controller Interface to be less user friendly than the keyboard for setting up certain commands.