Some lower-end front track hubs have 10mm axles instead of 9mm, which means the axle nuts would be the same size as what is typically used on the rear. I don't know of any 10mm axle nuts that have a rotating washer that would be smaller in diameter.

Even if a 10mm axle squeezes into those dropouts, they are designed to accomodate a standard axle nut for a 9mm axle.