[redshift]

Find out what the cops are using, that's maybe as close as you'll get.

Short of that, one of the keychain cams would be as good as you'll get, without IR obviously. Running off a DC-DC converter, and using a 16GB card you'll have nearly unlimited space. They are low-profile and the lens is in the laydown position. I really don't think you can do better for less. The timestamp would actually be a GOOD thing for your app as well. They are well under $50, (they are as low as $15) which means you could use more than one.