One thing I would like to know is how to properly get my NTSC Film based DivX into an NTSC Broadcast based MPEG-1, preferably using ffmpeg for the final encode...

The reason being: I love the speed ffmpeg has... I can encode one XVCD worth of video (roughly 60 min) in one night on an old 8600 running X. However, a lot of my DivX files use 23.97 fps, while my DVD player only likes NTSC XVCDs that are 29.97 fps.