The proposed Baldwin-McKinney-Nader debate that had been planned for Sunday evening, October 19, is very unlikely to happen. It seems that none of the candidates who were originally invited (including Bob Barr, and on a theoretical basis, the major party nominees) had really committed and really wanted to participate. McKinney and Baldwin have both expressed displeasure that communications between their campaigns and the debate organizers were not clear. Nader seems to have concluded that he will only debate with Barr (except, obviously, he would also debate with the two major party candidates).
It is still conceivable that a Barr-Nader debate will be organized.