Bam with all respect intended you are absolutely wrong. Have you ever seen the magnets used in computer HardDrives? If you got an old broken hdd go ahead and take it apart, take one magnet and put it on your palm, take the other and put it on the back of the hand. It will be a pain to remove, or for fun put it on the tips of your fingers and watch how much skin will be torn off before you can get the magnets to release.
I thought of that actually, attachable/detachable rear wheel covers, except my concept was of ones that were plastic and matched the truck, much how the Honda Insight has them. I also thought because you don't want someone jacking them you would have to cut slits in your fender wells, and then install 3 locking mechanisms such as these:
http://www.yaotek.com/store/Assets/P...es/2050033.jpg
Or many wall lockers have ones that when turned a long pole is extended through a hole in the top and hole in the bottom, I think this would be ideal.
Also Bam take a magnet like that and put it on your oil pan, most newer vehicles (I know mine does) have magnets on the drain plug to collect metal shavings, if you put that on the oil pan of an older vehicle it will do the same, so when you drain the oil you get more bang for your buck.
If someone made fender well covers that looked good on my truck, and fit as well as the honda insight I would pay for them, I think I would pay as much as $100, maybe a little more.