I have noticed that nearly all webpages scroll up/down. Why don't they have the pages scroll from left to right? I think that idea is nifty, and would spark curiosity from it's unique format.
But if the page stretched from top to bottom of the window and no further, then there would be no vertical scrollbar, and your wheel will scroll horizontally.
The problem with this idea is that for it to be practical, you'd have to retrain westerners to read large amounts of text top-to-bottom, left-to-right, instead of left-to-right, top-to-bottom.