food for thought whilst your laid up,
instead of electric, how about hydraulic, with a set of free wheeling hubs, I know that this application is used in Augers (
http://www.parkessteel.com.au/_product_49449/Hydraulic_Drive_Augers ) and cherry pickers, sometimes known as Hydraplats,
lots of logistical problems with a power pack, oil (extra weight), etc etc
how about a driven trailer via a pto shaft (diff) with free wheeling hubs,
anything is possible if you have the time, inclination and lot of $$$just more food for thought.............