My first thought would be to set the play in its original setting. But as I think about it more I would try to do something different. I would not make it set in a high school, as many other Shakespeare plays have already been done this way. I think I would set the play in New York, in the late 1800s to early 1900s. It would focus around a group of somewhat 'high society' kids. Each of the characters would be influenced by the rank of their families. Antonio would be the son of a wealthy Importer, and he is an starting to work for his father to make even more money. He would be a kind and naive boy, who lets people manipulate him. Bassanio would be the son of a once wealthy family that is slightly struggling in the stock market. He would do anything to get what he needs and even more to get what he wants. He would be always in debt to his friends. Portia would be the heiress to some giant fortune and would think of herself as to good for anyone that is lesser then her father was. She would of course have a kind heart underneath her cold exterior. Nerissa would be Portia's best friend from a lesser family. Perhaps a family that had be helped by Portia's at some point. She would be a resentful kind of person and be very much jealous of Portia and her status. Shylock and his family could possibly be from a wealthy family that has come from Italy to New York to expand their business. With this character he could still be much like the original character, and still be Jewish.

I believe that by setting the play in an earlier time frame but by making the characters be of a a younger generation would draw a large and varied audience. It would not be directed at on group or the other.