[Eexhaton]

Maybe I'm completely lost here, but help me out. Vibrations are felt. So how exactly would this manifest itself in the game? Should the image on the screen start shaking? Would your force-feeback joystick start vibrating?

A shaking image would be bogus because in reality, your brain compensates for vibration and you don't "see" the vibration unless it's extremely violent, very low frequency or both. A Merlin at idle is not going to produce enough vibration to have your vision going up and down. I've flown high performance piston engined aircraft and could always read the small print on the checklist or my lap board...even at higher revs when checking the magnetos and the prop. The brain does a good job at filtering out the shakes.

So unless you have a USB force feedback office chair, I don't see a realistic way to really simulate this. Or am I just way off base here?

A shaking screen when the engine starts perhaps?

The same way you see the screen shake when the guns are fired.