For sale we have a Stihl MS261 Chainsaw Motor w/ Bristol Drill Attachment- basically this saw has been modified to be a super high-powered/high-torque drill. Here is the description from the Bristol website:
Bristol's Drill, when attached to a Chainsaw engine, gives you the possibility to do all kinds of wood work. Can be used to construct fences, sheds, drilling masts, heavy or light works.
It can also be used as a powerful one-man auger for post hole digging, drilling where no electricity is an option, etc.