It sounds like it's in the works. This article makes it sound like both Radcliffe and Kastor are interested in going head to head. The only question is where: New York, Chicago, or Berlin? Any race that could get both of them to toe their starting line would instantly have a very interesting lineup.
With the possibility of two of the fastest — and most marketable — marathon runners going head-to-head this fall, the directors of three of the world's top races are vying for the chance to provide the stage.
Organizers for the three major marathons in the fall — New York City, Chicago and Berlin — are competing to arrange a showdown between two of the best female distance runners: Paula Radcliffe of England, the world-record holder, and Deena Kastor, who has the American record.