heh -- the metal bits (all the iron cage, iron gate, ironwood beam, etc) and the new dwarf copper metal as well are incredible anchor points and let you do this kind of thing.
I wish we had a bunch of metal grate patterns.

as for windows, the 2 crystal max width is annoying but you can make some pretty stuff. I have a rotated square (corner to the ground) of 45 degree black wood poles (4 pieces) filled with crystal in one home, and the gap-wall black marble can make a diamond pattern, while 1x1 anything (marble, rock, wood) can make a somewhat rounded window, and so on. you can also embed it into the fancy wood 2x1 decorative piece. I would give a LOT though if they would just let crystal stack 1 tile. Just 1.