BitmapData, get/setPixel on scaled data. Real get/setPixel exist?

Question

Ok... I've been staring at this all day long, so the answer might be screaming at me and I just don't see it....
Summary:  I need an Image to "show through" to the background, cutting through any other images that may be in it's way -- but not images on top of it (only below).
[Edit: Is there an on-screen get/setPixel alternative?  As it seems BitmapData's only let's you edit the raw (un-transformed) data.  I'd like to just write the actual pixels on the screen.  There has to be something that keeps track of all the pixels when the item is scaled.  ]
A picture is worth a thousand words, so I whipped up some examples in PS:
Imagine this is the app that consists of four Images.  The background (skyline), and the three layers stacked on top.  The smiley is the backmost, the heart is the frontmost, and the snowman is in the middle.
Notice how the snowman knocks out the smiley, but not the heart.  I'm achieving this by painting BitmapData with the background pixels wherever the clipart is not transparent. Also, if there was an additional layer (or any number of layers) "behind" the smiley, it would also be "knocked out" by the snowman.  This is why I'm pretty sure I have to do it this way with the BitmapData and manual get/setPixel. (Open to suggestions?)
This method does work perfectly... as long as the snowman isn't scaled or rotated.
Here, the snowman has been scaled up and rotated.  The problem is that the background image pixels get scaled up right along with the art. The outline of the snowman should only be visible when it knocks out the smiley, but instead you can see it clearly because the background pixels do not match, and are actually scaled/rotated along with the snowman.
This is how it should look even with the scaling and rotating.
Here is the code that is doing the "reverse mask":
this == Image
var thisWidth:uint      = this.width;
var thisHeight:uint      = this.height;
var targetWidth:uint      = this.x + thisWidth;
var targetHeight:uint      = this.y + thisHeight;
var data:BitmapData = Bitmap(backgroundImage.content).bitmapData;
var newdata:BitmapData = new BitmapData(thisWidth, thisHeight, true, 0);
newdata.draw(this);
this.content.visible = false;
newdata.lock();
for ( var x:uint = this.x, drawX:uint=0; x < targetWidth; x++,drawX++ ) {
     for ( var y:uint = this.y, drawY:uint=0; y < targetHeight; y++,drawY++ ) {
          color = data.getPixel(x, y);
          newdata.setPixel( drawX, drawY, color );
newdata.unlock();
this.addChild( new Bitmap(newdata) );
Anyone have any suggestions?
My current direction is....
1)  Is there a way to rasterize a transformed layer?  By that I mean make the current transformation permanent.  So, if an image was scale(1.5, 2)  you could function rasterize(image) and it would still stay scaled, but have scale(1, 1)
2) Do the calculations to figure out the inverse matrix and apply it to the bitmapdata before adding it as a child of the image.  This way, when the background pixels get scaled/rotated, they will end up in the right place.
3) Give up, quit my job, buy a sailboat and a lifetime supply of rum.

Answer 1

Winston, don't know how I missed this earlier, but in case you're still looking for some kind of insight, here's what I would suggest:
Keep your movies as .mov files, do not use .mp4
For 4:3 moves, use 768x576 or 720x540 as your size
For 16:9 movies, resize your movies to 1024x576 or 720x404
(Exactly what you use is more about how large you want your file sizes to be)
I know you've attempted very similar steps under the MPEG-4 options, but have you tried this:
Open Movie in QuickTime Pro
Press Command-E to bring up the Export dialog
Under Export: leave as Movie To QuickTime Movie but press the Options... buttons
In the Video pane, select the Settings... button, then set:
   Compression Type: H.264
   Frame Rate: Current
   Key Frames: Automatic
   Frame Reordering should be checked (this is crucial)
   Data Rate: Restrict to 3500 kbits/sec
   Optimized for Download
   Under Encoding, make sure Best Quality (Multi-Pass) is selected
   ... then click OK to exit this Compression Settings dialog
Now, back in the Movie Settings dialog, select Size and adjust that accordingly. (If you're using QT 7.1 or later, you can select whether or not you'd like to Deinterlace your video as well in this dialog. If you're restricting your use of these files to your computer via Front Row, you just might want to deinterlace DV-sourced material.) Then click OK.
Back in the Movie Settings dialog, deselect the Prepare for Internet Streaming option, then click OK to jump back to the QT Export dialog
Export your file (this is not a speedy process)
Or were you doing .mp4 files because .mov files weren't working out for you?
Dual 1.42 G4, 2GB RAM, 9800 Pro, 20" Cinema;   Mac OS X (10.4.6)   Final Cut Studio 5.1