First, it appears that Lockheed-Martin and Boeing will collaborate on the USAF/DARPA Blackswift technology demonstrator. (see below for notational configuration)

Additionally, we are increasingly seeing developments world wide in hypersonics. (Paid Subscription Required)

We have had a number of relatively successful tests in Australia and the USA, and the EU is funding Lapcat II and Atllas concepts (see below), in addition to efforts by France, Italy, the UK, and Germany.

The Russians are working on plasma concepts to manage the shockwave and examining their potential as control surfaces, with, “tests on a magnetohydrodynamic (MHD) plasma generator in a simulated Mach 5.15”, being conducted, while the Japanese are looking at a combined cycle turbine with a cooled intake called the “S-Engine”

In terms of meaningful applications, I think that some sort of storable fuel, not the LH₂ currently used for demonstrators, will have to be a part of the equation.