rice didn't do an equivalent to the kang flip until tita. however, he did the first proper double cork over pyramid in Pop. some people say jp walker did the first dub cork on a snowboard in MDP's shakedown because snowboarders referred to that rotation as a 'frontside cork' at the time. and he did two of those rotations, hence the double cork. but, its really a double flip not a double cork and is the snowboard equivalent to the kang flip.
and since everyone is talking about dub corks in the pipe these days, David Benedek did the first one in a pipe in 91 Words for Snow, (which i've been meaning to put on youtube) years before scotty lago and shaun white.