There's a startup based here in Chicago called FeeFighters http://feefighters.com/ http://feefighters.com/ I've never tried it, but they'll apparently do this

There's a startup based here in Chicago called FeeFighters http://feefighters.com/ http://feefighters.com/ I've never tried it, but they'll apparently do this for you. They get a number of payment processors to bid for your business, and the winning bidder pays them a referral fee.