Her US Open 2009 Cinderella run may be over, but she has a bright future.
The next Grand Slam event after the 2009 US Open is the 2010 Australian Open. Prices for futures with that tournament have not yet been released yet because, like the US Open, it is a hard court championship event. With that the odds for favorites will be heavily affected by the outcome of the yet to be decided 2009 US Open.
However if you wanted to find Melanie Oudin in the futures market you could look ahead to Wimbledon 2010. She made the 4th round there earlier this summer and she has only improved since that time as evidenced by her US Open quarterfinal appearance. As she will only be 18 years old in a few weeks a great deal of improvement has to be expected from such a young star.
Her current price to win Wimbledon with betfair is +5000 (50/1) and that price seems to have a lot of value at this point based on her recent results and the expectation of further improvement.
Look at Betfair for tennis futures.