Ventilated auto seats can improve fuel economy by reducing air conditioning load
But my wife always has the heated seats on all year long, cooling seats would only make her more frigged 
Your wife is more "frigged"?

That's funny. I can see 'frigid' but frigged is something different altogether.

As I've posted elsewhere, I found the air conditioned seats in the Benz SL to be a disappointment. I suppose they'd have minimal effect on the reduction of a/c load... but then, putting all that nonsense in a car adds to the weight which requires more energy to motivate the car in the first place.