Power

Energy Scavenging with Shoe-Mounted Piezoelectrics
Article on how to generate electrical energy by walking.
http://www.computer.org/micro/homepage/may_june/shenck

Human-powered wearable computing
Article describing the physical limits of generating energy directly by the human.
http://researchweb.watson.ibm.com/journal/sj/353/sectione/starner.html

Making a battery pack adaptor for the M1 HMD
explains with photos how to adapt a model-building battery pack for wearables.
http://elemental.org/~daleg/gargoyle/m1-batt-pack.html

NRG Research
Produce several battery belts and vests (and professional video lighting equipment). Catalogue online.
http://www.nrgresearch.com