Shaun,
I think the premise is a good one, but it will come down to the execution that will make or break it.
Having a cool car or two on site will be important, but you'll need to have "take aways" included like photos with the car/driver, a matchbox or model parting gift, and promotion on site for the purchase of a certain amount of clothing.
Refreshments are key and other activities depending on the age demo will be important so that you don't have people waiting in line to get close to the car, take pics, etc.
You should do this in conjunction with a charity that benefits children in need as well...all these components make it a very "sticky" event opportunity for your business.
Let us know what you come up with...as always, you know we're here to help!
