Difficulty instantiating to a custom class

I am trying to extend the GameObject class to allow me to add functions/methods that I can use without the overhead and complexity of static functions. I'm trying to instantiate a obj file from resources to an object of the new class (because, since it should inherit all of the members of GameObject, it should be able to do so, correct?), but I can't get the code to work (Javascript). A brief synopsis of my code would be as follows:

class ExtendedObject extends GameObject {
public var stats: int

function ManipulateObject(inputValue:int){
stats = inputValue;

var newObject: ExtendedObject = Instantiate(Resources.Load("MyModel"),position,rotation) as ExtendedObject;
newObject.tag = "Player";

I know I'm missing something in my understanding here... but I'm not sure why I can't load a resource to the object when it should have inherited all of the features of a GameObject. Any help would be appreciated!

The only problem I see with your script (potentially) is the Resources.Load() portion. What is "MyModel"? You can't instantiate models, you can only instantiate game objects, components, and prefabs (which are also game objects, inherently). If you want to be able to instantiate a model, insert it into an empty game object (by dragging it onto the scene), then create a prefab, and reference the prefab in your script. You also shouldn't use Resources.Load unless absolutely necessary, instead, create a public reference to a field in your script, and set its value using the Editor Inspector, like this:

public var myPrefab : GameObject;

Then, instead of instantiating using Resources.Load(), simply feed it the prefab, like so:

var newObject : ExtendedObject = Instantiate(myPrefab ,position, rotation) as ExtendedObject;

You're not supposed to extend GameObject. If you need added functionality, you're supposed to make components that you attach to your game object.

See here: http://unity3d.com/support/documentation/Manual/Scripting.html