Aw, Damn. You had my hopes up. This is Mahjong Solitaire, not Mahjong. The actualy Mahjong game plays much like Rummy. Any chance you could port a real Mahjong game with the Japanese (Riichi Mahjong) ruleset?
EDIT: Just to give you an example of Real Mahjong: http://www.4windsmj.com/intro.htm
However, the Four Winds Application is not open source. I'll link to an open source one if I can find one.
I loved that game on the Amiga: it was called Shanghai and was released by Activision
The only thing that I'm missing is the dragon that peels a hole in the green wall and looks at you after you finish the last 2 tiles. And the 1vs1 mode that has a countdown for each player