Well, not really.  Big Dog is making some big steps in terms of development.  Still DARPA wants it to be stronger, faster, and smarter.  They plan on increasing max payload size to 1250lbs, with that payload size being able to sprint at 10mph, and also want it to be able to trevrse obstacles without human assistance using GPS system for direction.  While its not Metal Gear, it sure seems like the start of it.  A robot that can move on any surface, delivering heavy payload.  Here is a video and you can also check out this article if you are interested.