I don't think you could do it exactly the way you describe, because the hard disk isn't spun up when you see the animation. Therefore it can't copy the animation into place before the animation starts.

However, there's nothing to stop someone from writing a program to flash a new animation AFTER the player is booted, therefore providing a randomized animation for the NEXT boot. The end result would appear to be the same from where you're sitting.

The problem is that the process for flashing the RAM is slow, and you will corrupt the flash if you interrupt the flashing process (for example, if you cycle the power in the middle of the process, or it reboots cause you were starting your engine or whatever.) So there'd have to be some safeguards in place. Also, the flash is a limited resource that can only be burned X number of times before it doesn't work any more, so anything to reduce the wear and tear on the flash bytes is good, anything that increases it, is bad.

I'm not sure if the player can keep playing while things are being flashed or not...