Zell Miller would never be selected because of his opposition to the 1964 Civil Rights Act.
Although this is true, it was curiously NEVER brought up when he gave the keynote address at the 2004 RNC.
anyway, McCain won't pick Miller. He's irrelevent now, about the same age as him, and his views, which have changed wildly over the course of his career (Miller is an even bigger flip-flopper than Kerry and Romney combined, but that's for another thread) have devolved into being reflective of 1950s Georgia. He might play well in the South, but he'd be toxic up north and out west.