I did a quick search and didnt see this posted, just thought I'd share a random idea I had to reduce frontal area caused by the leading edge of the tires.
Why not take a motorcycle fender with a very aerodynamic shape and attach it to the spindle of the car. Since the fender would be mounted to the the suspension, it would move through the complete arc of travel while maintaining the same distance to the road. That way you wouldnt have to worry about exposing more or less tire during compression and rebound. It could also reduce the need to run a smooth wheel cover if a compete fender blank was used like this:
In some ways this could also eliminate or reduce the need for wheel skirts if the trailing edge of the fenders were also curved to improve airflow while taking care of the issue of allowing extra space for the wheels to turn since the cover would turn with the wheel.
This idea comes by way of airplanes and the Aptera, but I see no reason it couldnt be adapted to a car with fenders, other than some possible mounting issues.
Any thoughts?