Ah, you mean the famous rock-paper-scissors game.
That could be done. They did implement it in CivIII, the boardgame, so why not. The boardgame is more limited in almost every other way (it takes too much time too play the computergame in all its facets on a board).
It's a good idea, and not that difficult, I think. But they won't do it for CivIII (too big a change), maybe Civ4. We can only hope. Maybe they can put it in the editor of CivIII, I hope so.