A nine patch or D9P with large squares will go very quickly. I did a hand pieced top approximately 64-65" square from 9 each 18" finished blocks (9 squares per block cut at 6-1/2") with 3" sashing strips and 3x3 joining blocks last week while sitting at the hospital for DH's bypass surgery and recovery. Now to get it sandwiched and quilted.
If you do the piecing by machine you could easily do that all in an afternoon or evening. Then all you would have to do is sandwich and quilt...the part that takes me forever...