You should look for the user macegr here. He has worked with narrow PCBs for LED bars, and I saw a couple nice designs.
The tiny black bit in the middle of the tiny green board is the accelerometer. You can buy the accelerometer ON the green breakout boards from Seeedstudio and SparkFun. It's hard to scavenge individual SMD parts from an actual Nunchuck. If you're on the mini, you could fashion a jumper so it doesn't get crowded in the staff tube. You need three analog inputs and two lines for power.