I don't know if anybody's seen this, and I have yet to make one myself, but here's a do-it-yourself mp3 player made out of an altoid box. The tutorial is here:
http://web.media.mit.edu/~ladyada/make/minty/index.html
With a preview:
It seems pretty straightforward, although some equipment might be difficult to acquire (soldering iron, etc.) if you don't have that lying around and are only going to do this once..
http://web.media.mit.edu/~ladyada/make/minty/index.html
With a preview:

It seems pretty straightforward, although some equipment might be difficult to acquire (soldering iron, etc.) if you don't have that lying around and are only going to do this once..