Check the following link for the California Car Cover Company.
http://www.calcarcover.com/default.asp?flash=1 They make custom covers in a number of materials. The fit will be nice and snug. Also, they have tie points so you can pull a tie cord under the car. That is the key to keep the wind from getting under the cover and causing it to flap (even with a fitted cover). You are right to be concerned about flapping. One of my subordinates used a "universal" cover on his new Camry and it wore through the paint where it touched on the corners. I have used covers for over thirty years, both on my drivers and my show car, and have come to the conclusion that the 100% cotton covers are the best for a car that is covered indoors or in a protected area. I think Cal Car Cover calls theirs "Softweave". In an odd twist on the normal, they are the best material, in my opinion, and they are the least expensive. All the other materials seem to have serious drawbacks. The cotton covers, even without flocking, are just soft like a tee shirt. Thats a good thing. Just one caveat. DON'T COVER A DIRTY CAR. Any cover will just rub the dirt around and scratch the paint.