I did try Grump, and though it is incomplete, and I only finished one floor of the first building this weekend, I wanted to give an idea of what I was working on, here is the link, .
Any questions, ask and I'll answer later, it is late here and I was pushing a little to get the pics up, that is my excuse for lack of any descriptions, enjoy .

Ah, so that was why the building was so open - it was for demonstration only! I was thinking that it might be for some kind of market. Trying to make sense of it and failing. The closest I could come was an automobile showroom.

Doors look like they may be the biggest problems, cutting a amooth semicircle can be a bear. You may want to think about doing a separate heet of nothing but doors. That way you do not need to be overly careful cutting out the doors, as long as you make any errors into the door not the wall - replacng damaged doors with ones from the sheet. You may also be able to fudge them a bit to allow for the foamcore bases.

The Auld Grump

In fact, that's helped quite a bit.

I wasn't refering to folding alone (I have done a bit of tinkering with sheet metal and sculpting), though. I was thinking about how to alieviate the problem of so much of the matboard needing to be edged when scored and folded, because that would ruin much of the illusion.

So, with your chamfering idea, that could be a non-issue.