Its been a while...

[slight]

sort of...
you can do this:

cloneMC = originalMC.duplicateMovieClip("cloneName", cloneDepth);
cloneMC.onEnterFrame = function() {
  // code for clone, or call another function here
  // with(this){...} is often useful inside dynamically allocated functions like this.
}

for checking if an MC is visible on the stage... if you have a mask layer which covers all other layers to stop the swf spilling out over the stage edges, you could convert that mask layer to an MC. That way your other MCs can hitTest against it.