Kirk - why don't you sell your brakes to somebody who has a 4.6is or 4.8is? Cash + their brakes in trade. I'm sure there is somebody here who would be interested.

One other thing you might want to check - the rotor size is different between the 4.4i and 4.6is/4.8is, but the calipers might be the same. You might only need to upsize the front rotors to get your 4.4i brake set up to 4.6is spec.