Noah, I seem to have missed some part of the process in DVDSP3, or perhaps it just shows up wrong.
1) I shot in 24P advanced... edited it fine, exported it as a 24P 16:9 movie (I made it self contained). It shows up fine in Quicktime Player at 23.98, 720x480 (2.9MB/sec.)
2) Took it into Compressor and made the m2V and aiff files. When I import the m2v file into DVDSP3 the rate shows 29.97 in the assets column. Is this a glitch in DVDSP3, or did something happen along the way in the m2v file? Perhaps I misunderstood... I thought I could make a 24P DVD?
3) One other thing, when I open the m2v file into Quicktime Player, it shows the right frame rate, but the size is 720x404, instead of 480. I re-encoding it again to see if that was a fluke.