I don think that is even possible. In Oblivion if you used the tfc command (free camera mode) you could see part of your character's body if you were in 1st person mode when you engaged the camera, but in Fallouts your character is completely unseen when doing the same.
There was an Oblivion mod for this. If I understood it correctly, what it did was create a duplicate, headless version of the player wearing the same gear, and use getpos/setpos and playanim to cause it to mimic the player's movements.