Another way to add depth to the spaces at the front of the house would be to widen the house. The back of the house could be extended all the way along. This would mean that the corridors would need to move as well. It makes better sense to move the front walls either side of the central bay forward. The issue then is what to do about the roof line. The extended sections could be left flat, capped with some sort of dormer. Or the roof could be raised and replaced. I'm not sure if we'll get permission to raise the roofline.
While you can change your floor plan in the future, remember you can't change the location. With this in mind, don't make the mistake of falling in love with a floor plan and forgetting about the property and surroundings of your home. If you fall in love with the layout of a master bedroom in floor plan, but don't like how it looks out over the street in the model home – chances are your home in your location will have a totally different aesthetic, view and therefore feel different. Remember when choosing a floor plan; ensure the interiors will fit with your location.