Gorgeous fabrics!
Yes, I agree, Attic Window may be just the pattern to use.
You don't have to have the center of your 'window' square......could be rectangle. You can add the window 'sills'/ 'ledges' to 4 sides but if parts of the surrounding kimonas are contained in the cut area, it may work better to add sills/ledges to just 2 adjacent sides.
http://www.crystalpalaceyarns.com/eq...ticwindow.html
http://quilting.about.com/od/quiltbl...ic_windows.htm
http://www.hgtv.com/crafting/attic-w...ays/index.html
This one has all sides sashed.
http://3.bp.blogspot.com/_pz8eid7Sg_...ssarts.com.jpg