I'm no engineer, but I don't think we'd even need to reverse engineer anything. As long as the vehicle runs over snow, the carburator and engine design of a moped should run fine. After all, my engine still did 25+ mph in several inches of snow.
The thing is just to find a way to build tracks. The replacing the front tire w/ a ski shouldn't be a problem. Dan and Simon demonstrated that. How does that sound? The problem is figuring out how to design brakes.
Like I said, I'm no engineer. But it'd be great if that could be built.