Don Cheadle is, according to a report from The Hollywood Reporter, stepping in to replace Terrence Howard as James Rhodes in the upcoming sequel to 2008′s summer blockbuster, “Iron Man”. Sources close to the deal are reporting that the replacement stems from financial differences in negotiations with Howard, and that Marvel Studios had initially wanted to work with Cheadle for the first Iron Man film, directed by Jon Favreau. In the comics, Rhodes is Iron Man/Tony Stark’s best friend and pilot, eventually stepping into to take up the mantle of Iron Man for a while before Stark returns after defeating personal demons. Rhodes then becomes War Machine, using a weapons-laden…