You'd probably need to lug around another battery to keep that metal spinning.

But consider this: With 2 8GB SD cards, your N800 has 16 giggerbyters of storage onboard. At an average of 400 MB per standard-length movie (and trust me, higher file sizes will not make for a better viewing experience), you can have something like 40 movies in your pocket.

Of course, that's only a fraction of your collection (if it resembles mine, that is), but it's still good for three full days of viewing, with only the bare minimum of sanitary stops. Sleeping is not included...