Posted here in part because this video of SpaceShipTwo's latest supersonic test flight manages to look very reminiscent of newsreel of Blue Steel launches!
About a decade ago I did my ICSC presentation on the potential military applications of privately-operated space planes (this was not long after SpaceShipOne had won the X-Prize for exceeding 100km). The credit crunch has slowed things down a bit, but it seems that Branson still has a big queue willing to pay 200K for their five minutes of weightlessness.