UPDATE: The zoomed sniper is unuseable in triplewide! You just see a stretched large black circle with a red dot in the middle of it, but nothing but black in the circle! Messed me up early in the game where you have to go thru training...will have to switch back and forth I suppose...
I realize this is an old game, but I wanted to play it before I played Conviction.
Followed the above to play single monitor 1680x1050 (center monitor in surround mode)...
Then I thought, hmm, noone mentions if triplewide works...well, it does! Videos and menus are stretched across all three screens, game looks correct though hud items are also stretched, but very playable.
SplinterCell4.ini
============
[WinDrv.WindowsClient]
WindowedViewportX=1024
WindowedViewportY=768
FullscreenViewportX=5208
FullscreenViewportY=1050
SplinterCell4User.ini
===============
[Engine.PlayerController]
DesiredFOV=141.22
DefaultFOV=141.22