This sled was based on an old Ski-doo I used to have. The hardest part to build: the steering, mostly because the handlebars can't move far enough for rack-and-pinion. Sorry its kind of hard to see in this pic, but the skis do turn about 35 degrees.
Here you can see the track: pre-8272 and 8275. The sled also has working suspension in the rear.
The hood raised showing the 2-cyl engine. doesn't really work, but hey, it looks cool. It could also be replaced with a motor to drive the track. You can also see the worst part of the model: the exposed drive gear and chain. I tried to fix this but was unable to.