If you, Post Praetorian, are interested in sticking around for a while, there are other multiplayer versions we could try out:
http://www.chessvariants.org/index/listcomments.php?itemid=HexShogi91-3
This is a 3-player game on a hex board as well, but in general it is simpler. The pieces move exactly as a hexagonal counterpart to the square board, for instance, instead of modified version. There are no rules for alliances, and if you read the description in the link, the author believes the nature of shogi does pretty well to counter the petty diplomacy problem as it is without special rules. What I like most about it are the victory/defeat conditions: a player must have all three kings to win, and does not lose if his king has been captured. A captured king must be dropped immediately, so a player can try to get a king back. These simpler rules could make for an interesting game and do surprisingly well to overcome the problems inherent to 3 player games. I am certainly more interested in the game we are playing, as I've wanted to play it for 18 years to see its complex rules in action, but this other game seems worth a try as well.
Also, I hope I could get enough players for 4-player Yonin Shogi, if you're ever interested. :)