Wow, those are nice! I used to make paper and card models of ships almost 30 years ago and dad did cardstock models on our HO layout way back then. I've recently been tinkering with building cardstock structures and, due mostly to budget, I'll be building many of my layout's main buildings out of cardstock, foamcore, plexiglas, etc. I apparently can't post pictures here yet but will post some of what I've done when I can.