If you mean "natural scrolling", you can do it at a lower level in linux by remapping the "buttons" with xmodmap. Gnome ignores the system setting for this (or used to, at least; I don't use any Gnome stuff now, so maybe they've fixed it), but pretty much everything else in X will obey those settings.
Yeah, but it was a checkbox option in settings, and not something people trip over... they didn't need to remove it, at least they shouldn't, without another way to do it relatively easily.
