Flash - Transform Tool Architecture?

I'm trying to get familiar with design patterns, modularity, unit testing and etc... (with ActionScript). I'm developing a simple "Free transform tool" right now, just as a exercise, but I don't like the solutions that I come up with so far, so I'll try to walk you trough my line of thoughts. When I come up with the idea I was thinking "What to write so I can test this great Unit testing framework FlexUnit", the first thing that I saw was guess what.. a free transform tool. :) When I was thinking about the architecture of the tool I run every scenario trough "How can I write unit tests for that thing?", so I come up with some kind of twisted MVC meta pattern:

A view that's holding all components (rotation area, drag area, resize buttons)A model (or something like that) that holds the necessary logic (setSize, setPositiom, rotateAroundCenter, etc..).And a controller that add listeners to the view components, update the mouse cursor when its over a component, get the mouse coordinates when is interacted with a component, do the calculations and call methods from the model that will update the view and the object that is benign transformed.

I was thinking: "Ok its flexible, i can switch M, V or C at any time, I achieved my main goal, because I can make lots of unit test for the model, where the important calculations are, so its great..".I just have started implementing it, but I think most of those thoughts are wrong. Yes I can change the view and add new skin but it's not flexible at all, if I want to add "skew" (or any other) functionality I should rewrite (or If I'm lucky just extend) M, V and C.Yes I can make bunch unit test for the model but controller's calculations will be hard to test.

So now I'm thinking for something like the Decorator pattern that will allow me to create whatever combination of controls i want to use and keep their logic separated, but I want to have the option to re-skin the controls themselves and to keep the logic separated so I can do the tests.I realize I want to create some kind of "ultimate transform tool", but I'm really trying to push my limits and learn something.