If I was designing this, I would only have a small set of "SKUs" with minimal customization, and then go all out on economies of scale. If 10% of houses switch

If I was designing this, I would only have a small set of "SKUs" with minimal customization, and then go all out on economies of scale. If 10% of houses switched to a single "system" with a small set of SKUs, such that everything is optmized for manufacturing, shipping and assembly - you could reduce the cost of construction significantly. This is basically an extension of the IKEA model for the house itself instead of just the furniture.