Isn't Grover Cleveland most famous for having a baseball player named after him?
Walt
Could be, though I think the story about the illegitimate child still comes out on top. Or maybe it's the fact that he was both the 22nd and 24th President. This was the closest the 19th century came to human cloning. President Cleveland is also known for having a daughter who had a candy bar named for her that everyone assumes was named after a baseball player.
Grover Cleveland Alexander, though, must be the only person to have been named after one President, and played by another in the movies.