As far as I understand all 2 stroke engines can run in reverse (sans water/oil pump issues and other things that glow engines don't have). In fact the new ski-doo and polaris snowmobiles use this feature for the reverse. When you press a button then engine idles down, and right before it stalls, the computer sparks way advanced and the engine starts spinning the other way. Not only is the button much lighter than a reversing gear box, but it's more reliable, and works better too.

Not really rc related but cool 2-stroke stuff non the less.