Mamet (the guy who wrote Glengarry Glen Ross and Ronin among other movies and has directed plenty of films as well) has just completed a MMA movie called Red Belt! He wrote and directed it and it is scheduled to come out in July 2008. Apparently when he moved to LA a few years ago he really got interested in MMA and even began training. There hasn't been very much revealed about the plot but it has a very good cast including Chiwetel Ejiofor, Rodrigo Santoro (I'd imagine both of them portray fighters), Emily Mortimer, Tim Allen and Joe Mantegna. Randy Couture also appears in it.