I remember watching a movie on Cartoon Network as a child with two men in top hats chasing after a girl in these very colorful, very vivid scenes. The only characters are the two men in top hats, the girl, and the villain who is kidnapping her (though I remember nothing about him). One scene I remember is the villain carrying the girl over his shoulder crossing a short bridge with the two men in pursuit.
The men in top hats were a anachronistic version of ATLAS and P-body from Portal 2, one being tall and skinny, the other short and plump. The two men were definitely something out of the late 19th, early 20th century.
The animation was very similar to Foster's Home for Imaginary Friends, but it was crisper, very detailed, except somewhat steampunk. Basically, the art style is very hallucinogenic. If I were to estimate when I watched it, I would guess around 2000.