I toyed with the idea of that snow/bike/conversion kit type idea, great for lightweight dirt bikes. The sohc 4's are too heavy for that chimpy little set up, not enough track to move the weight, and certainly not enough ski to steer ,now we're talking about 500 lbs with a high center of gravity balanced on ice on two points and one of them is gonna spin, ya get dead quick on that, that's why snowmobiles have multiple points and two of them are for steering.
For those southern members if you havent seen the way a snowmobile is put together, it's amazing, it's a cookie sheet with a motor.
I was looking into a removeable track type set up for a Rhino, but it would set ya back $3000+.
Those 3 wheeled Can Am spiders would be the machine to covert, I wrote that to the factory years ago,an all season machine, they haven't done it! It's made by Bombadiar, the very same people who make the track and everything else for skibdoo and other snow mobiles,Wtf ? for $15000 you can be a dweeb on wheels all summer and King of the hill in the winter on the same machine.
Interested in making a snow machine yet?