SoftTH (DX9 x86). Edit %USERPROFILE\Documents\WB Games\Batman Arkham City\BmGame\Config\UserEngine.ini. Fullscreen=True, ResX & ResY= your massive resolution (no border), AllowD3D10=False, AllowD3D11=False, TessellationAdaptivePixelsPerTriangle=0.
(PLP screenshot with bezel effect)