Christopher Johnson now has legs!
The legs (believe it or not!) are pool noodles. I carved them into the shape I wanted, then layered several coats of latex and modpodge to them. Once they were the thickness/texture I wanted, I pieced them together with sections of PVC tubing and metal hinges.
I cut two holes into his hips and added more PVC tubing. Elastic was threaded through the two pipes, then through the legs, so they could move in all directions (while still remaining fixed to the hips themselves.
Although the feet still need to be added, the legs sure help him look more substantial than just a torso.