Was "how about a brick version" about the chimney? Or were you considering replacing the metal siding parts with brick to make the whole facility brick?
Big chimneys/smoke stacks would make an interesting separate item. I've considered using HO ones in some places, in order to get the size of large urban factory stacks.
Old East- if the Bergen Laser one is too big for you, you might consider the Walthers chimneys. They used it in their Machine Shop kit and also had them available separately in 2 packs (I was intending to check if they were identical to the Machine shop one, but they are stored away). The one on the machine shop scales about 85 feet tall.