You might try placing the servos in a padded, soundproofed box, and leading the actuators out to where they're mounted using flexible shafting (rotation) or tubing with flexible push/pull (linear motion) wire in it.
Its too bad they don't make small servos with helical gearing; that would cut down on noise quite a bit...but as lefty's already posted, there isn't really a need for quiet servos for the market they're sold in.
:~