Porkshanks's "Ambience Enhancer" is a sweet little steampunk MP3 player mod:
I bought a pair of vintage Cannonball Empire headphones off Ebay and I disassembled and gutted them. I then transplanted the working parts of a Sony MDR-006 (that I randomly found on the ground at a bus stop 2 days ago!) into them, and viola! Cool looking 'old' headphones that work just fine with my MP3 player ^ _ ^figuring out how to get the speakers into the Cannonballs was not easy. I actually ruined the prototype trying to do it in an overly fancy way with a different pair of sony headphones.
So then I decided I needed some way to get my MP3 player to match my steampunk daily wear.
First I hand sewed a little cover for the MP3 player and attached the brown leather protection pad to it. Then I took a raw sheet of Brass and cut out the form, bending it into shape carefully and adding the lynch pins and strapping last. I wanted to be able to wear this on my jacket as well, so I created a little latch on the left arm of my jacket so it can be put on and off easily.
(Thanks, Littleoracle!)