http://dornob.com/hand-crank-travel-dishwasher-has-space-saving-spin-cycle/
Here is a first generation hand cranked field dishwasher. However, I can imagine a far more efficient version, about the same size, but powered with a small motor. It would take about as much effort as pre-washing dishes before you put them in a washing machine.
It is like George Jetson and his wife Jane go camping!