producing high performance micro-sized generators

Such ehergy harvesters are as design depending on the kind of movement you want to use There are either for linear or rotating movements

If you want to bild them you should first learn about magnetics, magnetodynamics and generators.

There are already such defvices used in aeronautics, batteryless recievers aso

Plenty of development going on out there. Examples include...............

- Magnetic vibration harvesting for producing energy using MEM technology

http://eprints.ecs.soton.ac.uk/10483/1/Micro_Generator_Power_from_Vibrations_-_4_page_abstract.pdf

- VIBRATION ENERGY HARVESTING MICROGENERATORS

http://www.perpetuum.co.uk/

- Thermoelectric micro generators

http://www.poweredbythermolife.com/index.htm

- Piezoelectric Energy Harvesting using Ceramic Fibres

http://www.advancedcerametrics.com/pages/energy_harvesting/

- Motion to energy micro generators

http://www.m2epower.com/index.htm

And plenty more. That should give you some ideas.