I agree that it's core research, but it isn't published anywhere. Their control algorithms are not public; even plenary talks from Mark Raibert don't go into the details.
The way the govt avoids vendor lock-in (in principle anyway) is by farming out the money to multiple vendors, especially as the progress moves towards real practical deployment. They did that with autonomous vehicles, and they're doing it again with legged robotics (http://www.darpa.mil/our_work/tto/programs/darpa_robotics_ch...)
However in this one area (legged locomotion) it seems to me that BD is far, far ahead of anyone else, unless that work is taking place in complete secrecy.
I like the design much better than BD's weighty quadrupeds.