Loaders can be added to the tractors with rear pumps without a problem, same principal as if the pump was on the engine (the last KM units we imported had engine mounted hyd pumps). You just plumb between the pump and the lift box, use open center valves and you are good to go. The hydraulic pump is mounted on the input shaft of the PTO so you don't have to run the PTO to drive the pump and the pump only stops when the second stage of the clutch is disengaged, if you push the clutch half way, the tractor will stop and the hydraulics will continue to operate. Not ideal but certainly very workable and becomes second nature after a while.