I've heard similar claims, such as this site:
THE CLONE PRESIDENT Here they put forth the assertion that George Bush is a bonobo(chimp) cross-over clone.
Its a bit unlikely to say the least, but it's got some funny pictures and it's good to read other people's opinion's when they've obviously spent a lot of effort on it. As in anything there are nuggets of gold in here- notice what look kinda like vertical pupils on the "GWB-door" close-up shot.