Three monitors

[Hunden]

Not sure if this will work for you, but this is the best I could do for my setup.
Change your center monitor to a resolution of 1440X900
Change your 2 outer monitors to a resolution of 1152X864
Change your conf.ini to

[window]
width=3744
height=936
ColourBits=32
DepthBits=24
StencilBits=8
ChangeScreenRes=0
FullScreen=1
DrawIfNotFocused=0
EnableResize=0
EnableClose=1
SaveAspect=1
Use3Renders=1

[GLPROVIDER]
GL=Opengl32.dll

[GLPROVIDERS]
Open GL=Opengl32.dll
DirectX=dx8Wrap.dl