I once tried to make a tractor following one from several wipper snipper/brush cutter gearboxes and heads (we'd get about a full season from brush cutters by several staff meant many dead motors but heaps of good gearboxes) but I did n't have requisite skills & tooling to complete. Idea was an axle with wheels to keep stable and at a constant height & a shaft to run from rear PTO. local engineers said it could be done but very expensive for them to build. the idea was to be able to reverse over near steep banks (too steep for a slasher) to cut the swarfs to a satisfactory height.

hope idea may help turn on a light bulb for someone out there.

cheers