Are you aware of this: https://openmv.io ?

It is a single board computer with camera. You can develop machine vision algorithms in python or in C. They have different sensors but I am not sure they have one with a large enough area for what you desire.

I can see how you would setup a single rail in a straight line with a laser/camera combination but don't understand how you would use a generated laser reference plane to setup a second rail.

Dave.