I had a wonderful blue Italian walk behind tractor at my old farm that tilled, pulled a wagon, a lister plow and a sickle bar mower. A grand machine that powers itself, adjustable handles so the PTO can be at front and the machine in reverse, wheels adjusted. I even used it to pull logs out of the brush.
They make diesel BCS as well, its a machine I am currently looking for, because I can make biodiesel from waste grease. I'll post about that soon.
Earth Tools has a number of implements for the BCS and sells several models.
And a video of a combine in use on a walk behind tractor. BCS sells a reaper binder for harvesting grain in Europe and Asia. Not sure if this is available in North America.
Here is another Italian walk behind tractor with implements for the small farm