Surprised that no-one has made a thread on this already.
http://www.bbc.co.uk/news/technology-24803511
http://en.wikipedia.org/wiki/Lockheed_Martin_SR-72
Looks like it's been in the works for a while:
http://www.wired.com/dangerroom/2007...ke_all_defens/
Should be quite the impressive beast when it flies, SAMs are going to struggle to reach it.