Ok you know the old terracotta elements from the past? I think that store could be done in foam with a good 1/4" over of either fiberglass or the spray on hard coat. I units, not as small as the old stuff with lots of seams but at major design points maybe 12 units.
So if building is wood or steel stud with plywood and stucco skin then with just some scaffolding and my friend form the past we could install. An exposed attic space would be good. If not then it could be all external with hidden fasteners. Public price here maybe 75,000. I said to contact me through my email for that reason.
If it is one of the design elements from your 'Town' and those are the only things that come close to that scale then;
I would make a pattern from foam and pull fiberglass molds. I would then produce Fiber glass reinforced concrete casting with front and back filled with blown foam and stainless steel lifting eyes and attachment points. The reason is that if you are thinking Chicago then weather is a big factor and life cycle also. A resin coated element takes a lot of upkeep.
Concrete can be produced with lots of high strength and various fillers that will be both somewhat light and very strong.
Also in the windy city you would have to have a union crane and installers do the work, the rest of us could only watch.....
If you do not want this to show up for everyone to see send to my personal email.
is there a way to learn this kind of stuff with models more simple?