Great stuff Denny. I too am a BIG fan of the LiFe packs for direct power on larger models. Add to this the power hungry nature of digital servos and the power requirements can be a bit stunning.
I have also found the RX's can boot at above 3.2v and think 3.5v is the real number (I think it is for Hitec stuff anyway!). So really 4v is the danger zone IMHO.
Makes one really wonder when servos became such power hogs. I guess it is when the got ultra powerful.
I remember the days of flying .60 size glow models with one aileron servo that had 37in/oz of torque. I never seemed to need more then......
A fantastic reminder of how important proper power is to our systems.