If you are not limited on the thickness of the rotor, you will find that a listing for a 67 Ford Thunderbird will fit the hub and the bolt pattern.
It is 11.9" od and 1.25" thick.
This is what was used on the Mustang Trans-Am race cars.
I would go in that direction and look to find a caliper that will work with it and your front Pantera hubs.
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