I was going to do the same thing, So I found a company in Huntington Beach and they quoted me $150.00 (powder coating). I have now decided that I like the stock look of the prius and will not be doing much to it other than tint (when I can find the time). I used to customize all my cars with poor result and problems coming from the customization.
Nothing better than a stock car, especially when it comes with just about everything.
This should be posted again now that the subject has returned. Some mention should be made about the plastic wheel covers which were put on by Toyota after their anti drag tests which were done in the "wind tunnel" design and were designed to "smooth-out" airflow around the wheels. Of course you can remove them for "looks" if that is your desire as they probably do little more damage to the airflow if you have decided to add "mud-flaps" to your car anyway.