You don't see one of these every day.
Bert Verwey, Member #946, found this homemade "Isetta snowmobile" back in 2005, and sent in some photos and a description. This is the article that appeared in MINUTIA, Issue 14, Number 1.
"Enclosed are some pictures of my latest find. It was advertised as an Isetta engine/transmission. It turned out to be the complete power train with original wheels and tires, brakes and back plates, and a perfect windshield. It had been converted into a homemade snowmobile. Two tracks ran around each set of wheels, and a trailer mounted on a pair of waterskis held driver and passenger. Controls were mounted on the handlebar and steering was articulated. Note the Isetta rear bumper on the front, the louvered side cover and single Isetta headlight. Also note the GM timing gears and chain used to gear it down a bit. All together, quite an ingenious setup. The late owner's family had a lot of happy memories of driving this thing around the farm."