Using maya. To be exported as .fbx into Unity engine. Maya has spline ik. I'll try that out (and check out the tutorial link you've proivided). Thanks. There will be plastic tie clips to hold bunches of thin wires. So I might start and terminate the rig(s) at those junctures.
Oh...Missed the Unity part. Soz. I know nothing about Unity TBH I think Vig's idea of two bones for the back and door sounds like a winner. Depends how much detail you want to get into the animation of the wires. This way will be great for just stretching the wires out but they won't swing or dangle really. Having said…