It's possible they already have one and we won't know about it until the political climate is friendly to it's existance. I would sure like to see the ChiComies faces when/if we ever unveil such a wonderful craft.
The president wants a bold new vision for future space travel, he should take advantage of the great american skunk works machine and make it happen. We don't have to know about it until it's a glowing success. (no pun intended)
Maybe a SpaceShip One / Nuke Rocket combo licensing would interest Mr Rutan if their were federal dollars wrapped in a black project just for him.