I really liked this quote:
"The U.S. government has hidden a German-built prototype of the flying wing in a warehouse since World War II." 
In the video clip on the website attached to the first post they talk about "the government hiding the aircraft in a secret government warehouse near Washington, DC". Uuuhhhh.... It's been in storage, not so secretely, at the Smithsonians "Silver Hill" restoration facility.
As for the being designed with stealth in mind - baloney! It is not much more than a scaled up, jet powered, version of the earlier Horten designs. Any design stealth (radar evading) properties were no more than happenstance and, of course, the radar of the day wasn't up to today's standards.
C2j