Sure for the after market, why not? There are a number of people who want racing, I'm sure they want some of that. In fact I wanted to see a new shape for the covers, and illustrated that feature in it my self. An illustration is far from an engineered design, but it's a start.
As for being aerodynamic, that's a trade-off but I'm sure it could be worked out in the wind tunnel. The old ones are inexpensive, with a little more expense and other changes it's a likely accommodation, IMHO.
Here is some inspiration.
http://www.mclaren.com/formula1/car/mclaren-mp4-x/