video splitters. the only true way to spread non multi monitor support games across multiple monitors and NOT be gliched by software (winblows) forcing Primary screen function and limiting you to only displaying FL on one screen.
Again pay close attention as to some will only stretch the video output over the monitors and you will ultimately end up with a fatter ship etc.
best alternative, get 4 monitors with the same pixel ratio (3:4 etc) put two above, two below and get a 4 port out splitter. Walla, in the price you payed for all 4 monitors and the hardware, you could have gotten a large flat panel with no seems in the middle of it;) But instead of 1 big monitor you will have a whapping 4:)
The issue here isn't being able to expand it using third party software, as I’m sure you can after a bit of effort. The issue here is the game wasn't designed for widescreen. The main issue here is Field of View. No matter how much you scale it, you aren’t going to see any more as the game renders the FoV, not the screens.
You can change the FoV in the Camera INI but this will get you banned and also from past experience in other games, doesn't get you the same effect as in game that support widescreen. The fact of the matter is the more screens you stack on for one window the further back you need to sit anyway, sending the idea into an endless spiral of pointlessness.
Multi Monitor applications are designed for different windows in each monitor, having all the monitors used for one thing is designed for home theatre etc. however you could just use a regular HDTV for that.
I use Dual screen for FL in one screen and then Skype etc in the other, and I use this for basically any game as it's more useful than having to move my head almost 30 degrees every time I want to look at something at the other side, which in game you'd to quite often.
Also, here is a quick comparison of the two without changing anything aside from the resolution and aspect ratio.
You can see from the comparison that no more detail has been added to my widescreen setting than anyone else that uses a normal resolution, giving no real advantage to mine aside from filling my screen.