slenzen;

that a good looking project.
I have used structural aluminum panels on houses and they are just fine structurally when using the .030 skins. But one of the problems was when covering the roof panels with dark colored cladding , it would cause the top skin to expand and making the panel crown up as much as an inch this would not be a problem if it stayed there but, when it cools at night settles to the original spot.

There are pros and cons to everything.

Metal SIPs have many advantages and the prices are better now. However, even if they cost a little more, in the cases that I've designed and built, I needed less crew and enjoyed the "flexibility" factor that comes with metal. What you have to know is how the panels are constructed. For instance, there is one panel manufacturer in Florida which hand-laid the skins!!! so the panels where not uniform - and they cost too much. The kind of skin is important also - aluminum is not good for a house. I was building Florida and New Orleans where moisture issues must be addressed. We built some schools and negative pressure from the chillers created a by product of condensation in 3 of them. They took the blame, but it could have been avoided by a simple assembly modification.

CMkavala, yep, a very cool project. Similar style that I want but I need it to be half the cost ;) Are all steel sips ribbed or do they come with smoother steel cladding similar to that project. It'd be nice to have a metallic silver sip that doesn't need to be painted inside or out for a modern home.

No, they come smooth as well, which I have on my own home, they are a little too sterile looking for my taste.
I do like the subtle ribs for the soffit it has more the appearance of vinyl soffit

Regarding aluminum skinned SIPs verses steel skinned SIPs. Aluminum sheet metal has twice the thermal expansion coefficient than steel sheet metal. Every 10 feet of aluminum sheet metal will grow in length 1/8 of an inch. Every 10 feet of steel sheet metal will grow in length 1/16 of an inch. This growth is present in a moderate temperature differential. In my opinion if you use aluminum panels and keep them around 10 feet long the 1/8 of an inch growth can be absorbed into the system. If you use longer aluminum panels say 20 feet, that 1/4" of expansion will damage the structure or break a moisture seal unless the panel joint, panel anchoring system, and building configuration are designed to accommodate the movement. I prefer steel SIPs when a project needs long continuous panels. Also, steel skins hold fasteners in tension and shear around 25% better than aluminum skins. Aluminum SIPs have their place because they are generally 40% lighter and much easier to cut but one must account for their significantly greater expansion characteristics.