heh.. "broadist" appeal!!! good pun!!
Cant have a girl on it due to everyone has different tastes in what a girl should look like.
Id say go for words.. if you use signs.. some place like Cal Trans or Highway signs.com will say you stole the image from thier website and people are a little to sue happy.
Would be cool to have a space on there where we could have a place to put a transfer of our own favorite cars on there now that you can make your own. Maybe on the back or something.
So i say.. use words.. no one can copyright that! Unless its a saying or something.