The surname Warren comes from those that hunted livestock that was considered a nuisance (eg: rabbits, hares, foxes,
cats, sorry, my daughter will not allow the last animal to be considered a nusiance
) and rid them off the land, or a gamekeeper. Hence, the term 'warrener'.
Ok... All players start with a 'warrener' tile, in a similar way to having an Abbey tile. On his turn the player may use the 'warrener' instead of drawing a tile (like the use of the Abbey). The warrener can only be placed in a hole (same way as an Abbey is played) and brings roads and cities to an abrupt halt, but not farms. The player that places the warrener on his farm scores an
immediate 100 points, in addition to any farmers points (of his colour) already on the field (as long as the field is complete). If there are other farmers of an opposing colour in the field, they are counted as minus points for that colour (minus 3 points per completed city, when the field is complete). Only players that have the 'official' surname of 'Warren' are allowed to use the tile. All other uses are illegal and lose that player 100 points.
How's that for a variant? I think this a good idea
Edit: BTW, thought i'd better explain, my surname is indeed Warren