A good friend of mine lives in a community church that was converted to a residence (see below). It's enormous inside, and extremely costly to heat; I don't think it was ever insulated properly. Her living room is one huge open room in the front. The kitchen and family room are located in a wing off the back that once housed kitchen/dining space and offices. Sometimes former residents and church members stop by, unaware that the structure is now a private home.
Speaking of industrial structures, this is one of my favorite behemoths, an old cold-storage warehouse located in an Albany, NY industrial district. As with those grain elevators, I think it would take mega-bucks to transform this building for any other use.