You've hit upon some of my favorite pieces. Any of Lang's opus pieces are amazing (I really like the rock climber that sticks out of a piece of paper).

Satoshi Kamiya's works are also pretty darn amazing (the wizard, the dragons, etc.).

Lang really brought out the science in origami (he's en ex-rocket scientist turned origami pro), and wrote software for calculating the fold patterns and extraction points from paper for pulling out points of manipulation (like limbs, etc.)