I hate to be the one to say this but ford is right dumb but right. If you are using their designs to make a for profit product without obtaining a license from them then you are infringing on their copyright.
This is deeper than just a calendar and has more to do with people using fords logo to make and sell products which resulted in ford sending a cease and desist letter to cafe press who is rightly scared shitless of the possible litigation that could occur and thus is playing it very safe when it comes to possible copyright infringement. Hence the removal of the calendar.
The whole thing smells like lawyers looking for anything to increase the billable hours and ford having their head firmly up there butt when it comes to enthusiasts wishing to fully enjoy their cars.