In reading Smack's posts, one should bear in mind that he automatically attacks any, and every suggestion of anything positive about steel boats, without having any experience whatsoever in cruising in , maintaining long term , nor building or designing a steel boat.
In other words, on the subject of steel boats, he simply doesn't know his ass from a hole in the ground, and never will, meaning his posts are completely worthless.
I'm a bit confused by your claim that a frame-less steel boat is particularly strong. Having operated many steel vessels, both power and sail, I have personally scalloped (between frames) a few, in conditions which were admittedly difficult, but by no means extreme. I cannot even imagine how a frame-less steel boat would have withstood those conditions, without sustaining severe damage.
In a collision situation I do not see that a frame-less steel boat would be any different than crushing a tin can, unless constructed of obscenely heavy steel. Though as you claim, welds do increase the work in construction, proper welds are stronger than the steel itself and longitudinally welding several smaller plates (rather than a single plate) as Joshua was constructed or hard chine construction, should be a significantly stronger build. Whatever you choose to call your technique, "monocoque" means monohull in French, nothing more or less, and is certainly not a construction method, by the way.
I am in no way contradicting the statement that a steel boat could survive an impact situation better than a plastic one, but even implying that this situation is survivable in one of your boats is pushing things a bit. It is pure conjecture at this point and I would be inclined to think that it would be less survivable in an "Origamiboat" than a more traditionally built steel boat.