Vlad,
having a long drive shaft could be a benefit!
You could place a transfer case about 4 feet from rear end and have the bus engine/tranny spin a prop
the boxes mud boggers use can handle the power/torque, and having an air shifted rockwell would eliminate the cable needed, just mount box backwards and use the front out put (4x4) to power prop
so who is building it? and when is the christening