Atmel AVR ATTiny43U - Ultra Low Power Microcontroller (0.7V) !
LM4671 - 2.5Watt class D amplifier chip. Recommended by the Audio Power Amplifier Design Handbook. Only available in Micro-SMD package.
Cloth Insulated Wire
http://www.guitar-parts.com/products/1198/Cloth-Insulated-Wire.htm
http://www.fabricaddictions.com/p/526689/aluminium-armature-wire.html
Wire Cloth Patent
http://www.freepatentsonline.com/7048830.html?query=7048830&stemming=on
http://www.freepatentsonline.com/y2006/0232650.html?query=7048830&stemming=on