These bindings were featured in Ski Magazine. The Fritschi Freeride for backcountry skiers. I saw the Warren Miller skiers wearing these types of dual bindings. The back frees up and you can use your ski's like cross-countries. The price of $300 at Black Diamond is reasonable because of the special nature of the binding.
I'm not a back country guy, but I dig gadgets.
The Black Diamond reference is:
http://www.bdel.com/gear/backcountry/freeride.php