These large 2-pane storm windows were quite a find and I wouldn't expect many people to be able to grab these on trash night. Instead of 2 giant windows, 4 standard windows would also work well.
One window (on right) on each is fixed and serves also as part of the frame structure. Other than that, just some 2x2x4 triangles of plywood and some 2x4's to hold it all together. Notice the hinges at top. They allow the left window to fold back com[pletely or be propped at varying heights.