This is more or less what we did. Our foundations consisted of a standard foundation wall (with a poured ring beam at the top to replace the more normal slab) with a set of piers set inside it corresponding to the posts. For reasons that are beyond me as I look back on the project we didn't use a sill. The floor joists sit on this wall spanning the width of the house and the walls are simply sat on top of the joists. The walls are a sandwich of OSB panels separated by home-made I-joists. We found that here in France the cost of geotextile was actually higher than the cost of 9mm OSB (per square metre) so rather than making the normal larsen trusses (ladders) we made I-joists with a solid web to separate the boxes for insulation filling.
Were I starting again I would have used a sill which would itself have supported the floor joists and simply hung the walls from the frame. Without the sill, there's nothing to support the bottom of the walls meaning that installation gets more problematic. In a typical manner this tiny detail snowballed into several days of tedious corrective work when I came to install the subfloor!
