Servos do emit some noise, the question is more if this noise is significant to your application. I'd be more concerned with rf noise than line noise and do my best to simply keep some distance between the servos and anything susceptible to this noise (the camera?).
If you're still concerned, you may want to look at the BEC (battery eliminator cicuit) designs incorporated into most speed controllers the electric flyers are using today. These use the same (higher voltage) source to power an electric motor (much larger than those in servos) and the receiver.
These are the guys to get in touch with.:
http://emfso.org/
HTH, Jim.