My HUD is exactly where it was before the update. One of my squad mates lost his hud, I asked him where he had it on his screen before. He left it in the default upper right corner. I asked him what size monitor he has, a 27 inch. So I asked him to look and see if his resolution had been changed by how the update detected his monitor.
If it's not missing because all the check boxes under "Flight" are unchecked, then it may be in the upper right hand corner outside of the boarder of your screen.
Hitech, can you create a dot command that will set the HUD box dead center of the screen for these players? Then they can move it around from there.