You can download their HD formatted movie here, after you have downloaded the movie, it can be transcoded into a plain ol' DVD:
ffmpeg -i Elephants_Dream_HD.avi -pass 1 -target pal-dvd -aspect 16:9 Elephants_Dream_DVD.mpg
ffmpeg -i Elephants_Dream_HD.avi -pass 2 -target pal-dvd -aspect 16:9 Elephants_Dream_DVD.mpg
dvdauthor -o ed_dvd/ -t Elephants_Dream_DVD.mpg
dvdauthor -o ed_dvd/ -T
mkisofs -dvd-video -V "Elephants Dream" -v -o ed_dvd.iso ed_dvd
Transcoding the movie this way works fine, except that during the top-down scrolling bits of the movie it's not 100% smooth, this might be caused because the HD formatted movie uses a different framerate than PAL DVD. I'm not sure on how to resolve that yet.