Well you certainly think a lot of your opinions, as I do my own. I have personally been in charge of transportation for a LOT of steel that went to shipyards to be used in the building of ships. Funny thing BS, a lot of it was rolled, or had been bent with a press brake. It is a good way to get nice straight lines in steel, something I am sure you know. Now as to why I want the building to have such a nice high clearance, I want to be able to rig the vessel inside in order to have it all ready once I am ready to move it. I would not leave it on there, I just would like to be able to get every bit of the rigging done indoors, all the stuff fitted and done correctly, then take it all down and transport it. I kind of doubt that it would be a bad idea to be able to do it, an even better one would be to have the building be located where you could launch the boat mast and all right into the ocean by using a nice travelling crane to walk it out and set it gently into the water, fully rigged and ready to test the engines and sails.
If you used a brake or roller to make some of the bends and shapes you would be able to get a lot more out of the steel than if you did not. The fact that you are braking the material when you pull it together does not mean that a method of braking it was not used, because it is either rolled or has a brake in it anywhere it is not flat. Facts is facts, and since even you are not trying to sail a flat piece of steel it had to get bent some way, I just thought I would prefer to do it a little ahead of time, and not as I was trying to make the hull joints. In fact in light steel like the kind you use I would think the brake would give some rigidity, like if you broke the two halves at the keel seam up to a 90 degree angle to make a flange to weld together there, now maybe you are using angle iron or something like that welded at the keel seam, but I think that if you ran it through a brake, or even a roller brake and put a 4 inch high 90 degree flange along the seam it would be easier to weld, and would have a really good structural load point there.
Maybe I am wrong, but I know the material would be much stronger and you would have the added benefit of that flange, which you could have to the inside or the outside whichever one makes the most sense to give you a structural reinforcement right there along the keel seam. If it were facing to the inside you could drill through it to mount things like the mast step, the engine mounts, and the other loads. If it faced outward it would act as a mini keel from stem to stern and you would have a centerline that you could use to anchor the keel on the cross section as well as the welds or bolts that you use from the bottom to the hull. If you wanted to do things like that to the design then you could, but of course you like to have it built in someone's backyard, take ten years to do it, and then have the poor original owner have to sell it and let someone else come in to finish it.
I think it is time you visited the origamiboats site and took a look at how we do things. It will show you that what you propose is irrelevant .The keel hull joint is 8 ft of 3/16th plate holding the side of any of the twin keels, around 1.8 million pounds tensile strength, times 4, so what would be relevance of what you suggest in a boat the weight of a 36 footer. I have built boats from Campbell River to San Francisco to Minnesota to Winnipeg. I don't think they would let me bring along the brake press and rolls you suggest as personal baggage on a plane.
It is the misinformation that one must have such expensive tools, which causes many a steel boatbuilder to go bankrupt and backyard projects to take far longer and more money than they ever need to. It would take hundreds of boats to justify them , no chance on a one off.