When exploring sensors for reading out behavioral (i.e. motor) output from an animal, I came across bend sensors that can be incorporated into clothing (http://www.talk2myshirt.com/blog/archives/724). By using thin copper foil, velostat, and epoxy, I was able to shrink the dimensions of the sensor to about 15 mm length. Unfortunatly, I needed something even smaller, and something more compliant. But here's the basic idea:

Construction steps

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Bend sensor construction: Sandwiched between glass slides

Bend sensor construction: Epoxy sandwich before trimming

Bend sensor prototype: A prototype of a Velostat / epoxy bend sensor. The sensor has a resistance of ca. 15 KOhm. When acting in a voltage divider paired with a 15 KOhm resistor, bending of about 40 degrees leads to a voltage change of about 1 to 1.5 Volts.