No, I have no idea if that would even be possible, given the limited space within the hilt, to place any type of MP3 player within it, and have it wired to the LED in such a manner... or if those type of electronics even exist for this type of situation.
What I do know, however, is there are some soundboards out there (such as the Spark2, which is the board SF uses in the hero tier) that come with a "Sabertracks" font package... you preload a song or two onto your SD card, and when set to that font and turned on, the music plays instead of the usual saber sound effects. There may be some customization that you can do with the LED in the settings configuration for the Sabertracks, but I'm not sure how indepth it is for that type of situation...