An idea for a mod using a two lcd screens.

[d_stilgar]

The mod would involve building an arcade style box. You would have one LCD at the back of the box displaying the game, everything but the HUD. You would then have another LCD showing a mirrored image of the HUD and the rest of the screen would be black. This would be laid down pointed toward the top of the box. The image would reflect off a piece of glass giving the effect of a 3D HUD over the game play images. This could be done for many games, although it would take a smart programmer to make it all work properly.

[AMD Killa]

That actually sounds pretty awesome, but like you say, will take some real skills to pull off.