Anyone know where/how to buy/make some curved vertical blinds for a bay window ? I want to be clever and make the slats wider than usual for their spacing, so when closed they will almost form a double layer of fabric. This is to give a greater insulating property, closer to that of curtains. They could be asymmetric to allow them to be closer to the window, but that might put them off balance (would depend on the mechanism). Thanks, Simon.