i'm positive the noise was from the instrument cluster, definitely from inside the passenger cabin.
when i first heard the noise, i immediately scanned the instrument panel, specifically the speedo and tach, and i did not notice any fluctuation in either reading. (the same thing happened to me in an old japanese car, and the speedo needle went wild, hence my reflex action to check these gauges). If the stepper motors went wild, then won't they register as fluctations on the needle readings?
if it is the speedo cable, then that is a comforting thought, as opposed to having yet another electronic gremlin.
i will have it looked into - thanks guys