Well I don't think its going to be any quieter than a 'normal' machine, the noise of the spindle cutting is the loudest sound and normally would drown out that of servos/steppers, also you will need a pumping system for the hydraulics and maybe a vacuum for dust control.
How would you get positional feedback for any controller to know how much to move any rams. Is there even controllers for the level of precision you would want from a cnc machine?
While I love to see new ideas i feel i would have to agree with CNC Lurker.
But anything is possible with enough smarts and cash
I'll get it finished sometime after I start it.....