My future homestead: the passive solar home

I've been thinking a lot about building our own home.  Not having it built, but literally building it ourselves.  Granted, Shayne's only building experience is a massively over-engineered chicken coop and shed, but both of us are capable of following directions and putting together a kit.  We've been considering Shelter-Kit, out of New Hampshire, to help us realize our dream of a cabin-type home.

The kits are post-and-beam, which allows you to customize the interior floorplan any way that you'd like.  The only restriction is the beams, which are 8' OC.  I designed the house to leave the beams in their original locations, though Shelter-Kit can move some of them around a bit.  I'm interested in passive solar heating and cooling, so I've worked to incorporate solar gain into the floorplans.  Here's what I've come up with so far:

The top wall faces south, and this orientation is perfect for our tentatively chosen home site.  The "front", on the right, will face west and the road.  The stove is situated in the stairwell, which is open to the roof, to allow heat to move upwards into the bedrooms.  The downstairs bedroom would be for guests and used as an office.  My mother may come live with us at some time in the future, and I think a main floor bedroom would allow her some privacy.  It would also serve as our bedroom if/when we are too old and infirm to climb the stairs frequently.

The garage would be sited to the north of the house, and the utility room would serve as our day-to-day entrance.  Being close to the kitchen and basement stairs, bringing in groceries would be a short trip. 

The "main" entrance on the west side of the house would be covered by a porch, possibly wrapping around to the north side.  The south windows would be shaded by 18" shed awnings to keep out the summer sun.  The kitchen, being on the north side, would help heat the house in the winter and be cooler in the summer.  Upstairs, the rooms would have skylights to help vent the heat in summer as well as bring in sun in the winter.  If finances allow, nearly the entire south upstairs wall may have a shed-roofed dormer, increasing solar gain.  I think it would add about $6000 to the cost.  The exterior would look something like this with the dormers:



from RRennerArchitects.com

Obviously, our home would be around half the size of this 3200 sq ft behemoth, but you get the idea.  Without the dormer, it would look something like this (view from the northwest):



From Shelter-Kit.com

We're going for a craftsman/cottage look (surprise, surprise). 

Let me know if you see any major design flaws!