This custom was a lot of fun to do.  I am not sure who desires the credit for the original concept of this figure.  Bunch of guys out there have some version similar to this one.  My Sentinel was made from a Mecha Hulk's body and the hands and feet McFarlane's Creech figure.  I used the articulated Creech, so the fingers, wrists, ankles, and knees all move.  For once, my custom actually gained articulation instead of losing it.  I sculpted his head using Milliput.  I ended up painting the whole figure black and dry brushed all the detail on him.  Unfortunately, this guy is so heavy that he doesn't like to stand without his base.  I super-glued the heck out of his joints, but I still can't get him to stand by himself.  Oh well, still like the way he turned out.