A 6 foot wide guillotine would work. Side supports are 6'equilateral 2x4 triangles, and a 6' wide window sash would be nailed between the triangles. The blade would go up and down within the sash,attached to a cable and raised by a hand crank, released when the wire is in place.The latch would be a single 7' rod with a handle on 1 side that rests in 2 holes drilled at either side of the top of the rectangle, It goes through an eye hook attached to the blade,Pull the rod back out of the eye hook and the blade is released. The blade could be a 6' long piece of T-bar sharpened and attached to a 6' long 2x4. The blade could be weighted on top with sandbags or small cans filled with sand or rubble. The bottom of the sash should be grooved to accept the blade but not the blade's 2x4.