ill throw in my 2 cents here... I have 2 giant scale planes a 40% Staudacher and 50% Pitts special which both planes have 2 li-ion 4800mah batts for one receiver feeding into a regulator then into a smart fly power expander with one switch. have had both set ups for at least 2 years now and countless flights on the staudacher and no problems what so ever... thats just one way of doing it. I love the way they are both set up and would not do it any different!

on my ailerons on the staudacher i do have 2 5955 servos on each wing half and 2 5745 servos on the rudder. no problems what so ever and they do great!
so i guess if you are asking about redundancy, the only major place i have that is with my battery packs and servos.