... Compressing that much onto a single DVD is going to cause very visible quality loss .. Yes it is possible to do so, but you probably won't like the results ... .. Run it through DVD Shrink multiple times ..
As catfreak stated you can run it through Shrink multiple times, but you will get pixellation on your DVD and it will take hours to encode. Why not just split it up, it would be better.
you could always just use a dual layer to cut out half as much pixelation and video loss on a single layer.... if you want to put that much info on a dvd, but i know you can also make a data dvd, but you need a standalone dvd player that supports it. i have jam packed a single layer dvd (over 6 movies) in 'data' format with nero. cartoon movies for my kids.... easy and fast to make, not like they care about 'quality video' anyway.