I have had quite a few lucid dreams myself and am also interested in the shared dream concept.A week ago i went on vacation with some friends with 1 of them trying to lucid dream.I had a lucid dream and got him to my dream , and told him what the situation was.But he didnt remember any dream so idk...But i still think its possible .Its just a matter of luck .Ur REM sleep has to be synchronised and u have to be open for brainwaves or something .Some study would be awesum