Energy Efficient Home Design Update

Please comment on the current thinking for a cost-effective home in a primarily cold climate:

1. Concrete block (steel reinforced and concrete filled) with either reinforced concrete roof or structural steel roof.
2. Earth-sheltered, walk-out-basement-style (exposed south side).
3. Integral garage buffers exposed side from living area.
4. Passive solar gain for exposed south side; dark colors for exterior walls, roof, garage floor.
5. Instead of the complication of radiant-floor plumbing or conventional ducting, the concrete home would be an open plan with a massive Russian hearth (masonry stove), with brick oven, at the center of the living area that naturally can radiate into the concrete floor.
6. The earth-sheltered, concrete structure would contain 100% of a home (kitchen, bathroom, i.e. all plumbing underground to prevent freezing), topped by a smaller, stick-built, 3-season, uninsulated "cabin cupola" (belvedere/widow's walk/lantern) with summer kitchen (solar oven or charcoal grill).
7. Electricity is undecided but I seek information on practical Stirling engines.