Looking at most of the rear view camera kits out there, the cameras rate for 420 line of resolution. Some say effective pixels 586pal or 486ntsc. So is there a technical reason why they are they are matching and selling 234 v pixels screens in 7"+ sizes?? Wouldn't a 640x480 screen be much better and 800x600 also work? I don't understand.

My father doesn't bother using his rear view mirror because the back of his truck is so often filled with equipment blocking his visibility. Hes changing the cap to a utility cap which doesn't have windows so there will definitely be no use for a rear view mirror and id like to ditch it for a monitor.
How would I mount a display to the window permanently, ie no suction cups? I didnt see that type of bracket for sale anywhere. Another option i was thinking about was getting one of those flip down displays,the swiveling hinge kind and attaching it near the top of the window. I'd mount the the screen and hinge parts from one. To make space for it up there i'd have to remove the glasses case, cut some plastic below and remove some thick fabric backing to the window edge. At least if i wanted the option of flipping it up.

I think an 8" monitor would work good there and fit in the space between the visors. My father has needed glasses for reading for a couple of years. He uses them to read small fonts on my 12.1" laptop screen but doesn't need them for the bigger fonts on his 4.3" gps of the same pitch. 8" would give a somewhat larger pitch than those screens at the resolution of the camera.