Ok.. just to test my suggestion.. of DVD2XBOX and XBOX MEDIA CENTER.
I just loaded dvd2xbox v0.5.5. Put in Buffy The Vampire Slayer - Season Three - DISC ONE, which is over 7 gigabytes. I pushed a to start the DVD copy process of DVD2XBOX, then picked the location to dump the DVD to (in my case F:\MOVIES, will be different for you, depending on the dump directories that you set up in DVD2XBOX), then I pressed START on my controller to start the DVD copy process. It took about 45 Minutes to copy/decrypt the entire DVD to my xbox hard drive (yep all more then 7 gigabytes of it). then I rebooted my xbox and loaded Xbox Media Center 2004-03-09, browsed to the directory that I had just dumped to and started playing on of the VOB files. The video looked perfect and played excellently. Just sharing the information, try it for yourself... and post your results here, or if you need help setting up Xbox Media Center 2004-03-09 or DVD2XBOX... let me know.... I don't know where someone is coming up with 12 hours for something.. but anyway.. like I said, it only took 45 minutes to dump/decrypt a 7 GIG movie to my harddrive. That's as fast or faster then my pentium 4 2.4 gigahertz serial ata system.