I have a Tetratec Whisper pump - and it's absolutely silent. But why do you want an airpump for such a large tank ? Unless you want to create an air curtain for effect (and that you can put on a timer and just switch off at night), there's really no reason for an airpump.
In that case, will over filtration not be a far better option ?
(that said, I know little about chiclids, though do know that Africans need to kept in large numbers - is this common practice in cichlid tanks ?)