Knowing I'm a fan of VWs in addition to these tractors, Tom Cain provided this story and pictures of a tractor owned by an acquaintance, Paul:
One of a kind Simplicity tractor
TRACTOR - Simplicity garden with 958hrs. Mower, plow, cab, and chains go with it. Limited slip rear. Front PTO.
MOTOR - Rebuilt 1977 1600cc Volkswagen Super Beetle 47-hp capable of being converted to 62-hp. 20 hrs since rebuilt and installed.
MOWER - 52-inch, 3 blade steel deck
PLOW - lifts by hydraulics, angles manually
CAB - hand fabricated and removable
TRANS - hydrostatic. He utilized an axle shaft from a
BMW to go from the Volkswagen to the Simplicity tractor. It bolted right up without having to do any machining.
From there on out it's all stock Simplicity. He made this tractor to plow his driveway and work in his garden. However, his wife was not too fond of it, and went out and bought a brand new Cub Cadet. Now this tractor is for sale on eBay.