So, I had some time to work on this problem, and here's what I came up with. Transcoding the first 15 seconds of the first chapter in the first title on the disc using FFmpeg and turning it into a MPEG-4/AAC loop works perfectly for about half of the videos. Here is the command I used:

ffmpeg -vcodec xvid -b 300 -qmin 3 -qmax 5 -bufsize 4096 -g 300 \
	-acodec aac -ab 96 \
	-title "$title" \
	-t 0:0:15 \
	-i "$dvd_path/VIDEO_TS/VTS_01_0.VOB" "$mov_path"

The other discs seemed to have one of two problems. One movie, “LA Story”, refused to encode the audio portion of the stream, yielding the error “Error while opening codec for output stream #0.1”. I was able to fix this by special-casing it and disabling the audio stream with -an.

The other problem is that many DVDs have menus comprised entirely of still pictures, which aren't meant to be played back at the normal frame-rate. When I preview them in Front Row, they just flash through all of the submenus rapidly. I haven't come up with a solution for this yet, but it might involve selectively setting the frame-rate to the lowest value possible.

I also still have yet to set the correct meta-data, since using -title with FFmpeg only seems to set the title property in the MP4 portion, and not in the QuickTime wrapper, which presumably is what Front Row and iTunes are using.