Patent US20100044134 - Snowmobile conversion kit - Google Patents
This is how the big company is doing it. I would change a few things, mainly the motor and clutch setup. I also think a simple racing go-cart front spindle and disc brake setup would work fine for about $100. Then the whole body needs a streamlined pod and a reclined seat with handlebar extentions. Maybe put airplane wheel farings on the front tires if room to turn still.