We just played a modified version of the 1st Edition Pacific game in my summer gaming class, using the Red Minis. It had 6 players, 5 Allied and the Japanese. The Allied were the U.S., Australia, British India, the Netherlands, China, and Japan. The Netherlands did not have an IC but could buy some units from the United States using income from the refineries in the Dutch West Indies and Lend-Lease credits. The Japanese player won because the Allies failed to cooperate effectively. Getting 5 middle school and high school males to cooperate is not at all easy, just like Allied cooperation in World War 2. It makes for a great learning tool.
Playing any Axis and Allies game with more than two players makes if far more interesting than a basic two-player game.