I stumbled upon a video by RoTechnic, who built a 6DF robot arm to hold a camera for them. And they did something amazing! Such a simple concept, that it blew my mind! And now I'm considering using this idea for Kevin's legs.

They're using fishing line inside bowden tubes to transfer the torque from the motors to the joint.

This makes it possible to place larger and heavier motors (and gears) where they're not negatively impacting the robots motion (as much).

In my case I would place the motors driving the outer two joints of each leg inside the robots body, saving a lot of weight in the legs, which makes them move faster and needing less torque.

It's such a great concept! I love it!