Craftster.org's user Cereallad modded this 80's boombox into a laptop bag for his iBook:
Basically I hollowed out the boombox, added hinges and clasps, created a foam interior, created a strap attachment, and... well, attached a strap. Now it holds my ibook and one or two other books.
With rudimentary electronics skills, I wired the boombox to play music from the laptop or from any ipod/walkman/etc that you place inside. I added a small amplifier that I found on some toy speakers to increase the sound volume and quality. Don't worry, I respect others when I play music. It's my school backpack first and foremost.