Bob,
Has your motor actually quit like you describe above, or is that just a hypothetical comment?
If it has, I would think you could set up a soft low voltage cutoff that just starts to lower the available power when you hit the LVC. That way if you are that close, you would probably have enough power to make the deck!
I don't know how much you guys have gone in trying to optimize your propeller (I bet you have). I know you want to go fast, and then during the slow part of the flight, want to have power available in order to quickly get out of tough situations. Anything you could do to get a thin light prop--but one still able to hold together would certainly help on the energy conservation point. The light weight feature makes it easier for the motor to spool it up fast when you need the "r's" and need them quick in slow flight (saves power because it can be accelerated faster than a heavier prop). The thinness would help in the high speed part, just to make it easier to turn the rpms you need in high speed -- but without fluttering of course.
Also there are new high "C" (40-45) packs by Thunderpower, Hyperion , and Polynoname (I think that is right) that have very low internal battery impedance. They should provide more available energy to the motor, but you need to be sure that you the high C rating doesn't translate to extra weight over lower C but higher capacity packs. Just a consideration.