Not entirely KF related, but certainly Tripwire related, Darkest Hour has now been released as a free official mod for Red Orchestra: Ostfront and downloadable over Steam. Darkest Hour finally brings the Americans to Red Orchestra, focusing on the beaches of Normandy, Operation Market-Garden, the Battle of the Bulge and on into the Reich. Featuring airborne parachute drops and late war German and Allied tanks Darkest Hour brings an all new style of gameplay to Red Orchestra.
Go here and check it out now: Darkest Hour Steam Page