It Exists
If anyone's still looking for a way to change the boot animation, there's a nifty program:
http://www.coderforlife.com/projects/win7boot/
Note that it turns off checks for DLL signing (by switching to "test" mode), so if you're really super-worried about Windows's security (like MS seems to be with their "reasons" for not allowing this in the first place), keep a good AV program around.
But, yeah, it works. The site tells you, but I'll mention it here:
To make a custom animation, it must be a 24-bit BMP containing a vertical strip of your animation (105 frames, 200x200px each, so a total size of 200x21000px). The program says it can use individual frame files and combine them, but it doesn't seem to work well with that (producing only a black image), so I suggest making your own BMP strip.
Here's the method I've been using to create my own animations:
1) I load up Adobe AfterEffects and create a new comp, 200x200, 15fps, 7 seconds long.
2) I create my animation as desired, making sure the last 3 seconds loop well.
3) I export as a PNG sequence.
4a) I load the PNG sequence into Game Maker 8 (the free version will work just fine for this; can be downloaded at yoyogames.com) as a sprite. GM will save animation strips, but only horizontally and as PNG, so we need to do some workarounds here.
4b) In the GM sprite editor, I rotate all the frames 90 degrees counter-clockwise. Then I export the image as a strip with File->Save as PNG.
5) I load the horizontal strip into MS Paint, rotate the entire image back 90 degrees clockwise, and save as a 24-bit BMP.
Done.
There are some considerations to keep track of:
1) The animation must be 200x200, so if you want a different aspect ratio (like widescreen, 16:9), you simply change the height to 200/A (where A is the aspect ratio) and then letterbox it to 200x200.
2) The framerate can be whatever you want while making the animation (as long as it's 105 frames and the last 45 frames loop), but since it'll be played back at 15fps, it's best to keep it that way during creation.
-IMP
