This looks interesting. :)

A wheel hoe equipped with an oscillating blade makes for pleasant work. The operator walks forward at a steady pace while making smooth push-pull motions with the arms. The push-pull takes full advantage of the swinging action of the oscillating blade and keeps its cutting edges free from debris.

http://planetwhizbang.blogspot.com/2...wheel-hoe.html

Site has plans available for building your own.