I've been doing searches for this, but I can't seem to find it anywhere. There was one MOD for Oblivion that, when a helm such as a hood was equipped, changed the first person view to have a black mesh in front of your face or something to make it seem like you were really wearing a hood, and it obstructed your view in first person a bit, just like a real hood. I thought this was extremely immersive and would love to see it in Fallout 3.
If I can find the Oblivion MOD, I'll link it or draw something to help further elaborate on what I mean, if most people don't get it.
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Cipscis: Helmet FOV v1.11 by XMarksTheSpot @TESNexus: http://www.tesnexus.com/downloads/file.php?id=8991