Time for the proverbial spanner in the works.
If you are in NTSC lands, and your source footage is HD at 24fps, you could always try encoding to the 24p MPEG-2-DVD setting.
This will put the progressive scan footage on the DVD at 24p, without degrading it to interlaced - and on an upscaling player you will get output at 24p.
If the disc is played on a non upscaling system, the player will automatically pull to 29.97, so you lose nothing and gain a lot.
The Adobe Media Encoder does a fine job of the 24p for DVD encoding as well - just remember to render out as elementary streams (.m2v and .WAV) - do not use the Dolby Digital encoder at this point (unless you need the SurCode 5.1 of course) and use LPCM - let Encore handle this.