http://www.chessvariants.org/contests/10/vesquj/vesquj3.html
This is the game I was talking about, to quote:
'The President, as a modern head of state, does not lead the army to battle. In fact, the President cannot move unless attacked! If in check, the President may move by trading places with any piece on the same side except a Sergeant. (The military whisks her away to a refuge.)'
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My vote, from the current list, ordered by preference :
A. Tony Quintanilla's suggestion (which is, in short, designing a mutator.)
B. Winning Conditions other than mate. (Losers, where you have to get mated.)
C. A game with Triangles as cells.
D. Specific type of Board : The Central Squares.
E. Multiple Boards. (1+)