Download the FOV hack for Mirror's Edge 1.0 and 1.01, using the link below.
It will make the game Hor+ in TripleHead, with displaced/stretched HUD and 2D elements.
Suggested FOV hack settings :
For 3840x1024 (3.75:1) - Aspect 3.75, FOV 0.012575
For 5040x1050 (4.8:1) - Aspect 4.8, FOV 0.013500
For 5x1-P + bezel (2.995:1) - Aspect 2.995, FOV 0.0089
FSAA set to 4x might cause the game to crash while using the FOV hack in TripleHead.
The main menu and all fonts will also look odd in some resolutions. If you want to change some of your settings and are unable to read the in-game display options, open this file :
\EA Games\Mirror's Edge\TdGame\Config\TdEngine.ini
and edit the following :
MaxMultisamples=
ResX=
ResY=
----------------------
I found a way to run ME all maxed, including PhysX and AA 4x, at 5040x1050 (around 60 FPS) with my 3-way SLI rig, by forcing wtih Nvidia Inspector, in Mirror's Edge profile, SLI rendering mode to SLI_GPU_COUNT_ONE. Racer_S hack was also used of course. Dont forget to update game to version 1.01 (the patch includes some physX fixes).
Another option is to use FlawlessWidescreen by HaYDeN:
https://www.flawlesswidescreen.org/index.php/Flawless_Widescreen
/!\ Do NOT edit TdInput.ini or the picture will be pillarboxed /!\ Thanks luluco250 & imusrt.