that is a cool model,,
were it me, I would go with a LiFe battery, they have few ( if any) of the issues inherant in a nicad,, you do not need a regulator like you do for LiPo,, they have no memory, so you can charge them from whatever state they are in..
a couple notes on servos,, mount using the screws through the rubber bushing like they say,, you dont want the servo hard mounted, especially on an IC model,, especially on a profile IC model since more vibration gets transfered.
I mount my recievers with velcro, which acts as a form of vibration dampening...