You know, people go to great efforts and even buy special camcorders to get that "film" look. But it sounds like to me that you have an MPEG2 encoding issue. For best results at least cost, you should try Tsunami MPEG Encoder, aka TMPGEnc. You can get it online at
http://www.tmpgenc.com/.
This program has had rave reviews, and deservedly so. You have virtually infinitely adjustable quality settings to as to maximize use of the DVD while still maximizing quality. The MPEG encoders bundled with other software usually have only three choices and will err on the side of saving space.
I just noticed when I went to get the link the TMPG, Inc. is now offering a DVD Authoring program. If it is up to the standards of their MPEG encoder, it might be worth a look.