The "how it does look" looks far more natural to me. What you are trying to achieve (seems to me) looks like it would be three separate cameras at different angles to look 'OUT' the side window. Unless your side-monitors are at an extreme angle, I'd stick with the way it is. I do notice the stretching in the top picture, actually a little more stretching than I get here.
Thanks for uploading, as I understand what you want. A good hint for you, (assuming you don't already use/own) would be TrackIR, then you turn your head slightly to see out the window like you want.
Do you use SoftTH or have a hardware solution for the triple? I believe SoftTH (which I use at this time) has some correction stuff that helps a bit with the stretching, that said, I still get the stretching - and you always will unless there are multiple rendering points. High FOV values will start to break down the rendering math as I was saying earlier.