I really wanted a dash cam so I could capture asteroid impacts. :) I got the cheapest thing on sale at Amazon. What I found is that for Linux you don't need all the fancy stuff, since you can't display gps anyway. You just need 1080p, and a 32 gb micro sdhc class 10 ability. I just put it on the dash with 3M Command strips, other people might want to be fancy.
I used Openshot to trim the video, and that is great stuff. Now I just need something exciting!
Added: I've tested at night, and it is quite good. It gets warm, so I wouldn't park and leave it in the window.