Here is a lightweight robotic arm with 3 highly-integrated Powerball modules to offer 6 degrees of freedom. It can carry loads of up to 6kg. You can combine it with the SDH 3-finger hand to do even more with it. The robot can be operated on battery for 8 hours.
This robot arm has a weigh/load capacity radio of 2:1. It offers smooth movement, making it ideal for humanoids.