Sorry I did not see this post sooner.
What's happened is that you have spooked the fabricators by letting them know (whether verbal or subliminal) that you are not going to be building structures but just flipping them. Since you are not going to be buying a structure from them, they don't see how they are going to make any money off you, and there is some degree of pride they take in their drawings and don't just want someone out there potentially "sharing" them with others unless it leads to an order. If you are building the same type of structure over and over -- and only need one set to pull infinitely many permits -- then you may be money ahead to just buy the engineering (but not for $1,500, more like $500) and use it on every application you file. The other alternative is to start over, and tell people that you are actually going to build the structures, get the engineering and then decide not to build it after all, The spin is more important than the actual action (as many people get the engineering and don't move forward and buy a structure, but the intent looks legitimate). I have never had to pay for engineering in my entire life, so I don't think that's the norm. But if you are unconvincing as a potential customer who will place big orders for structures, then it's going to be tough to get.
Have you tried some of the national fabricators, like Keeler Iron Works? A big outfit, that sends out a lot of engineering, might be less uptight about providing you what you need.