I remember (obviously unintentionally) reaching +6000fpm in a 737 while the autopilot was climbing in VNAV SPD passing FL360 - we suddenly gained 35 knots of headwind within 1000 feet, what we did was leave the autopilot attempt to fly the speed and kept the thrust levers where they were but pulled the speed brake in anticipation of losing that headwind component again to reduce the climb rate - eventually levelled off at FL400... Quite the experience, V/S pegged and Mach approaching 0.82 with the autopilot wanting to pitch past 10°.