There is an interesting shogi variant called Microshogi, aka Five-minute Poppy Shogi, played on a 4x5 board. It has a unique promotion rule - whenever a piece makes a capture it flips over and becomes the piece shown on the other side. The full rules are here:
http://www.chessvariants.org/shogivariants.dir/poppysh.html
I think it would be an interesting addition to the site. Minishogi players would particularly enjoy it.