You're absolutely correct in the case of an MB, especially the 103 motors where the oil drain plug is more to the front. I'll keep the 2X12 thing in the back of my mind. Might also work for a tranny fluid change. I have a 103 motor in a 126 chassis and actually manage to drain oil from the bottom as you do w/o lifting the vehicle. I simply pull the large shroud from underneath to gain access to the oil drain plug. In my case, ramps come in handy when you want to do a thorough under-carriage review - look for leaks, etc.
The ramp approach has been good for alot of Asian models that have the drain plug placed more to the rear.