Honeymoon Cottage or Tiny Residence

As I look at this drawing, I shudder at how small it is, but I remember all the years of my youth when motel cottages were common.  We have become spoiled over the years, and like most things in America, spaces have become SUPERSIZED.  We cannot seem to live without a king sized bed...or larger.  I remember these tiny cottages, which are sometimes offered as condominium units in resorts at several hundred thousand dollars a pop, having tiny electric or gas heaters, and sometimes communal shower rooms(buildings) and toilets.  Ah the romance of a communal shower on your honeymoon.
Anyway, this is dramatically larger than those old cottages, so I suppose it will be OK, if you are creative.  Everything is sized to just a bit more than the bare minimum, with room to walk around the bed, a little kitchen, and a small bath with a dual purpose linen and clothes closet. 
Smaller than normal fixtures would help in all cases.  An under the counter fridge, which is standard in Europe for a family, an apartment sized stove, a small toilet and pedestal sink will not be hard to find.  If you are frugal, you may have room for a big shower, and if you put a nice deck on the front of the house, there would probably be room for a hot tub, half the size of the house!  If you start the construction of this house with ten rather than eight foot walls, you might get away with extending the main roof out over the kitchen and bath,  I would absolutely extend the roof out over the front to provide shade for the glass fronted bay, but if you are going to use eight foot construction, you will absolutely need to make a gable end at right angles to the house for the two 5x12 wings.
Face the house to the south south west as described in very early posts, and extend a pergola out over the deck for vines to shade the deck and front of the house.  Either that, or plant large trees in front to cast shadows in the summer.  Use something tall and deciduous so the leaves will fall and provide solar gain for the winter.
You could replace the front window with a masonry wall, and a tiny wood stove, but local codes will restrict the wall space and heat shield issues and force redesign of the bay to accommodate it.  Not a big issue really if you plan in advance.  Tiny stoves are available, especially if you look at European sources.  They will be fine for mild climates or three season use.  I once looked at a house in Italy that had a heating chamber the size of a cracker box, and it heated the house.  It had ingenious piping to maximize the heat extraction.  Of course, Italy in general has rather milder winter temperatures, and they are used to keeping chilly rooms.  They have great gas heaters available there, too.
A full sized fireplace or stove, might require a dramatic redesign of the space, perhaps utilizing the bathroom wall as a site for a fireplace or wood stove and heat shielding masonry wall.  In that case, I would use the masonry wall as the wall for the bath, to conserve room.
I have marked the interior wall dimensions, and have placed a little mark on the walls where I suggest a window.  The clunky asterisks are sites that I suggest a little oval window or stained glass.  Where there is a plain dot, I suggest the possibility of using a glass door as an option.  Exterior dimensions will depend on the size of the wall studs, either 2x4 or 2x6.
I have made a scale drawing for you, but have ruled it on the outside of the space to approximate the thickness of the 2x4 construction.  You should try to preserve the size of the interior if you go for 2x6 construction.  You can up-size with no problem, perhaps going for the nice easy 12 foot dimensions where possible, but going smaller will undoubtedly feel cramped.
The two arrows are the suggested deck perimeter location.  Use recycled plastic bottle, deck materials to get maximum wear if not minimum price.
The entire house could be on posts with no problem, but do not try to extend floor joists out into the wings across the entire width of the house or the bay.  They should be treated separately with a double rim joist separating the main space from them.  Also, support the line of those interior walls from below.  In other words. you are building three rectangles and a trapezoid when you make the floor and foundation.  They just happen to be touching each other.
Also, as with any house, give extra support where you place heavy stuff, like a masonry heat shield.
If this is to be year round, you also need to be mindful of a foundation that will protect the plumbing from the elements.
Concrete blocks on a nice poured footing might be a good solution for this, especially if it is in a remote location.  If you draw a rectangle out of the wings and the center of the living space, you could do a full foundation there and put the bay and the bedroom on posts.
If you were to be really creative, you could easily site your shower at the front of the house and use an aluminum and glass door for the back wall of the shower in common with the front wall of the house, leading to the deck and perhaps a hot tub sited outside the bath.

You could certainly use part of the kitchen for a closet or something else, especially if this is a "summer only" cottage and will have an outdoor kitchen.  However, I feel gyped if I do not have plenty of room in the kitchen.  I like to cook, and feel that having a nice kitchen is a luxury that makes other sacrifices worthwhile. 
Many feel the same way about a bathroom.  Personally I feel it is a strictly functional space.  But, many people would gladly give up plenty if they can soak in a big tub or have a large and luxurious shower.  That is why I suggested the outside door to the deck from the shower to a hot tub.

I will continue this post in the near future, with floor joist patterns and bay framing patterns for roof, floor and walls.