I started with a regular DV camcorder mounted onto a bar mounted onto the passenger headrest supports. At that location, you will probably need a wide angle lens adapter, assuming this is for DEs and you want to see A pillar to A pillar out the front window as well as your hands/steering wheel.
Relatively cheap these days, great quality, high res video, and most camcorders will do well with changing light conditions and interior/exterior brightness differences. But watching it you have to deal with tape winding, and if you want to upload, you have to connect it to your PC, transfer, edit, etc... becomes a bit troublesome to deal with. Would avoid hard drive/CD type camcorders if you go this route, the vibration is a problem from other people I know who have tried.
I then shifted to a "digital" recording solution a couple of yrs ago. Went with a Hoyt bullet cam (was cheaper than ChaseCam at the time would still take a look since I think they use the same Sony electronics for the bullet cams), connected to an Aiptek MPVR mini digital camcorder (was ~$100 at the time). The Aiptek camera/optics absolutely suck, but it does take a standard video input and converts/records to MPEG. So the bullet cam is just providing the video signal and the Aiptek is just digitizing and recording it. Nice thing about the Aiptek being a "camcorder" is that it has its own display screen, which is useful when mounting/aligning the bullet cam, plus I can play back and watch the video on the spot.
Nice thing is that I just take the memory card out, pop it into the card reader and I can just watch it on the PC as a video file. I only record at quarter VGA resolution, so I think about 2 hours will fit on a 2GB card. My bullet cam is only 380 lines of resolution, so more than enough for QVGA.
With the bullet cams, because they have a wide field of view and are lightweight, image stabilization is not really an issue IMO. There are probably newer/better digital video recorders now.
Assuming you are recording goal is more to be able to review what you did on the track, and aren't planning to produce a high def video, you can go with lower res digital solutions. lucid, I can send you a sample video if you want to see how it looks.
Golden Gate BMWCCA - Car Control Clinics
'13 C4S/'12 328i/'04 GT3
Past: '09 M3 DCT/'03 M3 SMG/'95 M3... missing an E30 I suppose...