Things to consider ...When we are putting more receivers and more batteries and more swithes and more servos up in the air we are introducing more possible failures.
In my club there's a few electronic guys flying F5B and 10 cells racing gliders with big folding props in the nose and 100 amps flowing through the esc's and they have long ago designed their own heat sink circuits for the rx and servos. Us mortal F3A guys have adopted the system because it generates the best performance regarding instant supply of electrons without huge drops in voltage known from Nimh cells. For my Integral, which was the first all digital servo ship for me, I started with 4 2500 AA NIMH cells and did some testing on the table and I was surprised to see the voltage could easily go to 4 volts with all 5 digitals connected and operating under a little stress from my hand. Absolutely not good enough.
The circuit is based on the regulator from Micrel, MIC29502WT and it is usually used in harddrives or other constant voltage apparatus and I have put a picture of the setup in my Integral. 2 lipo's 1300 mAh provides plenty mileage for a flying day.

Note the big cooling fin, that is the required size fin whenever the regulator delivers up to 5 amps and 5,1 volts !!!! Without the fin to dissipate heat to, theres a risk the heat will destroy the regulator