I was thinking having my artist rap until he would normaly be out of breath and stop. Have him go back one line, and then continue on untill he runs out of breath, and repeat. That way it would sound like he never took a breath. I would have him go back a line so that when I actauly edit it all together it sounds a little more natrual. The power in your voice decreases as you run out of breath, so having it sound natrual is the tricky part, but if you stop at the right place, like before he completley runs out of air, I feel it is doable. Has anyone tried this?