In this Brazilian TV show, the host did several tests with a blond woman, a gay man, and a black man to see who would experience the most prejudice at a mall in São Paulo. While not very scientific, the experiment was revealing and at the end, even scary. I think it would be interesting to do the same test in the United States, except with a Latina woman or a Middle Eastern man. It might also be more interesting in both cases to use all men or all women.
UPDATE: Original video link stopped working - here is a new one, below.