here is a HV setup discussed. (tried and tested to)
Lipo will be the new breed. (holding the hand firmly of brushless)
And a higher voltage will also be suffering less from the internal ressistance.
for that reason electricity we have got in our houses is transported at several kvolts. (thru 'high resistance' aluminum wires.. )
In small words; At higher voltages it's easier to be more efficient.