Also, how do you plan to get away from the image of metal box houses being tied to shanty-towns and favelas?
In the west we don't have favelas so while I think it would be a down-point, I don't think there would be such a strong negative connotation.
Certainly, but the thing with expensive cities is that the hard part of that is finding the space and meeting the legal requirements, not getting the box.
That's also the problem in suburbs (though the space problem might be a little easier, legal requirements are at least as much of an issue.)
Isn't near every apt just a box, with slight changes around the frame? The question is how you carve up space within the box