Actually, there is at least one ride with barf bags - Mickey's Fun Wheel of doom. The swinging gondolas have them (I don't remember if the stationary ones do).
One of the more popular remedies for motion sickness, if you're willing to go to your doc, is the motion sickness patch that goes behind your ear. It can cause some drowsiness, but most people tolerate it pretty well. It's something you'll want to put on the day before you plan to ride, it takes a while to kick in, but it stays on for a few days.