Extending Robot Neck

There seem to be lots of choices for robotic arms, but does anyone know of a robotic neck with the following requirements:

  • Vertically telescoping from around 12" to around 30"
  • Top of neck horizontal platform or vertical mounting tab maintains +/- 2 degree directional (heading) alignment,
    or if rotates has encoder for pointing angle sensing
  • Light weight construction - around 12 oz with drive mechanism
  • Single servo / or dc motor (around 1A stall current preferred)