it possible to rewind motors, tho I've never tried it. In concept its simple, in practice I guess getting it right isnt so easy. I also read somewhere that dismantling a stepper can have an adverse effect on the magnetisation of the rotor so you lose a shed load of torque. Here's a thread on rewinding hi-performance motors for RC cars... I guess the techniques are much the same... http://www.xmodsforum.co.uk/showthread.php?t=761