The New York Red Bulls have managed to add another top name to their MLS roster this summer as Everton's Tim Cahill gets set to join their ranks alongside Thierry Henry and Rafa Marques. But would a franchise like the Columbus Crew or the San Jose Earthquakes have been able to lure in a player of Cahill's caliber?The MLS is built on the idea of parity. It's what sells the game to prospective franchise investors and to the fans themselves.Anyone can win the MLS CupBut is there really parity in the league? The designated player rule is one that I've always had a little trouble with.It's great that it allows MLS to attract some of the biggest stars in the game to America's shores, but it is also beginning to take away that edge of fair play that the league is so proud of.Where have all the top designated players (DPs) in MLS gone to?Los Angeles and New York are two sides that spring to mind when looking at DPs in MLS.Thierry Henry, David Beckham, Rafa Marques, Robbie Keane, Landon Donovan and now Cahill, have all made their way to two of the biggest and most fashionable cities in the country.Not ...