I want to build a 3 camera recording system for a truck?

If you have the electronics experience to build this all yourself using parts from digital cameras, then yes it could be done. Of course I think that if you had that experience, you wouldn't be asking, you'd be building the system.

Instead, look at low-end security cameras. Easy enough to rig them up on your truck, running back to a laptop for recording purposes. Low power, designed for the purpose, and easy to find. They also have outdoor models in a box and ready to go, although a little extra silicone doesn't hurt on those. Cameras for less than $100 each.. and an interface to a laptop for another $100 or so. You could even use a WiFi cam on the back of the trailer.. although the signal may be spotty while traveling down the road.

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The cameras would have to have streaming capability.

If you can get them to stream video, then it depends on how good of an electrical engineer and software programmer you are.