How much quality do you really need....really?
If you don't need HD quality you might look at what I do. I use a point and shoot camera that also records video onto SD cards. Works just fine. Plus I have the utility of the still camera all in a very tidy package. There are two that I use:
Canon SD 600 and a Canon S2 IS. I can chop the video in Quicktime Pro without having to recode them.
They won't hold a candle to a nice video camera as far as ultimate quality, but more often I prefer the ease of file handling and compact size. I can put the little sd600 in my pocket and the S2 is fist sized so its easy to toss in a bag or glovebox.
You can find deals on either the SD or IS cameras as the new models appear.
The newest is the Canon S5 IS, but you might find a closeout deal on the S3 (S4 was skipped):
http://www.dpreview.com/reviews/specs/C ... n_s3is.asp
http://www.dpreview.com/reviews/canons5is/
If you can live with a lower resolution (320 rather than the 640 setting), it will work just fine.
Another thing, most folks look too hard at the maximum telephoto length when they would really be served better by a wider angle lens at the other end of the zoom...especially in a car. That stands for any camera you buy.
I generally prefer the S2 in the car for its wider angle which allows me to see A-pillar to A-pillar and that it takes AA batteries.