Updated Design

Here is our latest.  The building is rectangular, with a stepped gable roof.  The long south facade presents an improved oppurtunity for solar gains, but the north face is also longer, where more losses occurr.  Of course, a large part of the gable roof is available for solar collectors.  Outside dimensions at walls are 43' x 31'.  All walls are 24" thick, and insulation values are about R70 walls, R100 Roof.  All cellulose, with likely some mineral wool in the basement.  No rigid foams or virtually none.
The view is of the South and West facades.
To give the south facade untrammelled solar exposure, we've moved the main entrance to the West side.  the challenge we now have is to make the entrance obvious and inviting.  It is almost like having one of those snout-nosed garage designs, where the visitor must travel around the garage to reach the front entrance.  In this design also, he is to travel around to the side of the house to enter, all the while remembering the importance of solar energy!  We are playing with those West roofs, and may even make them somewhat enclosed.  The building has a small enough footprint, we have room to spare in the lot coverage allowance.  The East side faces the street, where there is a balcony attached to the 2nd floor master bedroom in that tower-like stone-covered end.  Below that is an adaptable space where an elderly couple can stay on the main floor - they have an entrance to the garden under the balcony.

View from the South West.