Disgraced former Gov. Eliot Spitzer has been privately talking with friends about a possible comeback, and is considering a run for statewide office next year, several sources told The Post. Less than 18 months after he left Albany in a prostitution scandal, Spitzer has held informal discussions in recent weeks about the possibility of making a bid for state comptroller or the US Senate seat currently held by Kirsten Gillibrand, sources said.