Why not use the idea from the rag quilt but not make it rag? Cut all fabrics into squares of the same size, 8"x8" for example sew them together randomly, sandwich and do an all over FMQ. It is easy, quick and you can make them even faster if you cut all your fabrics in wide strips. Sew them into a wide tube, cut the tube to size of the blocks so you get the rings,and undo the stitches on every ring at the different place which will give your rows. Connect the rows and your top is done. Good luck.