SVCD in NTSC system has 480x480 resolution, while DVD has 704x480 resolution. Same encoding MPEG-2 for both systems. I captured home video of my bro wedding and encoded as DIVX. What can I say? I was able to fit around 30 min of video on one CD-R without seeing much quality sacrifice (was little one though). When compressing more, quality was inacceptable for me. So even if you make perfect DIVX rip from DVD, I doubt that MPEG-4 codec is almost 10 times more efficient than MPEG-2 codec. 2 hours movie to take 2-3 GB - sound reasonable for SVCD but 700MB using higher resolution than SVCD (heh?). Obviously I never watched DIVX movie on my TV. I had to reencode movie from DIVX to SVCD or VCD and when I watched it on TV I was not impressed at all. Obviously I loose quality on each reencoding but Divx rip was not looking great on my PC. As with any MPEG codecs, you results depend on video material, lots of motion will eat bandwitdh, lots of black (lots of same color in one scene) will save lots of space etc. I suspect that using 1 CDR for 1hour of movie would render better results.
Originally, I wanted to convert my home videos to SVCDs but now I got DVD burner and want to create DVDs since issue with home videos is excessive video nice which eats too much valueable bandwith in case of SVCD. Most likely I will use one hour video for 1 DVD to make sure that quality is as good as on tape.
DIVX vs DVD is subjective subject same as MP3 vs CD. Some people claim they are same, but I disagree. When listening on good sound system using monitors (speakers) or higher-end Sennheiser headphone I notice the difference right away and it is quite disturbing. MP3 users don't realize how much they miss because they use cheap headphones and on these headphones difference will be none.
You can read more video related topics on vcdhelp.com. Very interesting.