If they were to put a DVD drive into an iPad, it would have to be thicker, heavier and the the battery life when using the drive would drop to about 5 hours.

Also, if you play an HD rip on an iPad, you can actually see a difference in sharpness, despite the iPad not having an HD (720p or better) screen.

There should be a way to automate ripping. Like stick a DVD in, have it rip automatically and then sync the rip to iTunes so that the next time you sync, the file is copied over.

Otherwise, what does iTunes charge for movie rentals?