Godsend was slated to be the last 3.5 book U_K wrote. However, he's since turned exclusively to 4E, so now it seems very unlikely that it'll ever be released.
One ray of hope is that U_K is willing to sign off on 3.5 conversions of his 4E work that certain persons do, so that might result in something along the lines of Godsend being released someday.