Indeed they do. Some are designed that the top 2/3 is as wide as a 2-liter bottle and the bottom 1/3 is the standard size of a cup. Though this works in theory I've rarely met a cupholder that could, in practicality, hold this monster.
Generally the cup holders are either right up against the dashboard, shifter, or door. So the cop 2/3 wouldn't fit anyway. Cupholders in the back seat are usually in the center, unobstructed. but you can't sit 2 big gulps next to each other.
