My dad built two earth-sheltered, passive-solar houses that were always comfortable, required no cooling, and cost about $100 a month to heat over the winter. It's absolutely do-able but you won't get a house that looks like a "normal" house so people won't be interested in buying them.
I've still got the plans and if I had my druthers I'd build a whole mess of them all over so people can see that sometimes weird is much better.