RE: single battery possible?
1* 3000mAH 2S Lipo. 1*8A switching regulator (cost £10). 1*3A switching regulator (cost £4).
Corona 35M receiver (about £10). 6 digital servos and 26cc CRRC pro with Melody ignition in my 70" Yak.
Absolutely no trouble at all. Wish I had ditched the 5 cell 4300 nimh and 4 cell 2100 nimh ages ago! [8D]