I found this old 1920's Magnavox horn in an antique shop and repurposed it as a portable iPhone speaker. The base is hand carved from two walnut scraps. Sound amplification (or more accurately, maximized efficiency) is completely acoustic; the dock is not plugged-in or battery powered and the sound is enough to fill a room. I chose to not over-design the walnut box to highlight the well-aged, patina of the horn.
http://gadgets.boingboing.net/2009/04/27/old-timey-iphone-doc.html