I'll jump in here on this one as I have working on perfecting designs with these for several years and will be starting the first one (model home) next year.
My approach from the beginning is that it is a non standard building material and therefore every aspect of it must be fully engineered. We are modifying them and combining them with conventional frame structure. We have engineered everything including how the wood portions are attached to the steel. Everything was done in a very expensive Solid Works computer modeling program that could simulate stress loads on each portion. My engineer (who is extremely meticulous) said there was no other way to do it and fully document structure/code compliance with wind loads, braced wall lines, etc. You simply cannot assume it is "strong enough" because it is out of steel.
On ours you do not see any of the container and in fact it is more like a strong steel substructure. The first house is 28' wide and 40' deep and if you drove by you would assume it was simply a modern design house.
I have tracked many of these being built over the past 8 years and here is what I see a lot of: starting with containers that have been taken our of service (de commissioned) and no longer certified. Unless an engineer inspected that specific unit for damage, etc., he cannot properly stamp drawings since he doesn't know the condition of the box before it is modified. Next is insulation and thermal bridging. Unless it is completely encapsulated, serious thermal bridging will occur. And I have seen architects bite hook-line-and-sinker the myths about ceramic sprays--they are almost all bogus claims.
As a builder/designer, I monitor this forum specifically to learn from all of you and over the past several years and learned many subtle aspects that I might have otherwise missed. We will not only have a code compliant home, it will be superior in many ways.
