The same thing happened on my '03 about 20,000 miles ago (has 70,000 on him now). I was looking through Kmart, Target, AZ, AAP, Pep Boys, Wmart, Murray's/O'Reilly for a non ghetto looking wheel cover set, but the ones that looked ok (only ok) were 14 inch like on a car I used to have or 15 or 13 in. I searched sites but nothing was different than the stores have. I tried ebay for police style center caps, and lost on a buy it now set, and got outbid by $1 for the second set I tried for ($52.01 they went for). I checked a boneyard and they suggested a local body place, and wonderfully they had all 4 for cheaper than the others would have been with shipping added.

I paid/charged a total of $53.13 for all four and may put them on tomorrow.
So check the junkyards and body shops for replacement wheel covers. About 20 years ago I had a car with rally wheels on it but kept losing the centers and went with aftermarket covers. If it's possible, maybe there is a Ford or Chrysler 16 inch set available at junkyard that you could paint so the logos aren't as noticeable. I was going to do that with some older Taurus covers for the impala, but they were 15 inch. good luck and let us know what you find.