michael, it might take a big board, but we recently tried a 3 player everyone for themselves, its on the battle reports I think. basically the board is a big circle, each army has a area to defend and spots in that area worth points, plus they must attack their enemy clockwise to try and gain their points. assign a number of points to use and a minimum of 40% must be used to attack and defend, check it out, the rules are on there if you cant find it let me know.
its hard with odd number of players, the above is about the most challenging we have come up with as it is more or less fair to all players