(Probably) Stupid Question About OEM Cameras

Feel free to move this to a more appropriate forum if necessary.

So I had a random idea today: Could you record footage from the OEM rear backup camera if you tapped into the video feed? Also, isn't there some sort of OEM front camera that is used for lane departure warnings? I'm not sure what kind of quality this one would be, but I think it would be an interesting little project to tap into one or both of theses sources and wire it up to a Raspberry Pi or something similar to have the video saved to an SD card. It would be a super-discreet dashcam. What are y'all's thoughts on this? Is it possible? I don't mind how "practical" it is, see notes below

I like the idea of having a dashcam in my truck, especially one that has front and rear footage, but I'm not huge on the idea of mounting stuff on my windshield. It's not necessarily a deal-breaker for me, especially with some of the more discreet options, but I'd rather keep things looking as OEM as possible. Furthermore, I like tinkering with things, so I'm really just interested in this for fun more than anything.

 

I'm probably going to do the mod where you can view the front/rear camera at any time and thus will install a cam in the front grill anyway, so forget my thought about whatever camera may be installed OEM up front for lane departure assist.