That is pretty cool! Reminds me of my day in Legos. It was only about five years ago, I was a lego master. I was way into Zoids, man I wish I had pictures of some of the stuff I made! Just about any Zoid on the show, I made. And that is what this reminds me of. You should make a four legged one now. With a range of de-teachable weapons and stuff.
Cool stuff! When I get more of those kinds of joints I will make sure to re-create some of my older designs (if I can remember them, hopefully it will come to me).