i dont know if somebody is still checking this post, but anyway...
It really looks amazing and living somehow "underground" is also cool about concealing position ;D
Somebody where i live made something similar: bring loads of low-impact materials from far away and build a really nice house. But i find, in some places it would be lees impact building with just whats around already. I dont know what kind of materials where available in the place of http://www.simondale.net/house/index.htm.. but here there is no clay in kilometers around, no reeds, ... etc.. I find it quite sad when still people watch this house at my village and just focus on the look but forget about all the energy invested to bring this house here.
another point is about the civilized way of housing. I mean... I would call "low-impact" to increasing the amount of people living under the same roof.
sorry for been so critical, I'm just pissed off... but this houses really look nice