we did a house this way, but using wood studs.
One disadvantage was that the wall components are exposed to the weather. This was mostly a problem when waiting for the electrical inspection.....we also had a scare with a thunderstorm after the insulation was in place.
Can be done though. I can also say that that house is well insulated and comfortable. The walls were 6" fiberglass and the roof was 10"
-Mark in ontario.