Yes. Yes it would, actually.

Rewiring the entire way Allegro does displays for a tiny percentage of the people who use the game, and even then they'd only use it in one specific instance. THIS IS LOGICAL.

Wait, but just explain to me why it can't just be made so that this is easier to do:

Monkey ontop the left monitor ftw.
Very interesting, this could be helpful in many ways.
Do you know in Two players how the player who is aiming using the mouse gets canceled out when the keyboard player presses a key to move around and such?

Probably would lag up a whole lot. Unless you have like the best computer on the market.

Ok. Sorry for necroposting. But how things are going with dual monitors support in 2015 ? Or some ways how i can split game-window on two monitors?

(Sorry for my bad english)

I have a dual monitor setup working flawlessly with cortex command. I posted about it somewhere but I can't find that post.
Anyway, you need to run the game in borderless-windowed mode. For this, make sure your settings.ini is set to fullscreen = 0. If your monitors are different sizes, your resolution in settings.ini should be twice the smallest x-resolution by the smallest y-resolution. If this crashes, you'll probably have to shrink at least the y-resolution a little bit. The next release should have better borderless-fullscreen support. Use this program to force CC into fullscreen-windowed: https://github.com/Codeusa/Borderless-Gaming/releases/ . Use it to set cortex command to a custom window position. The origin should be at 0,0 (or shifted down by the difference in vertical-resolution of your monitors) and the other corner at your resolution defined in settings.ini.
I have a global script that forces either horizontal or vertical splitscreen since CC seems to choose the wrong one and since the settings for it are broken. I'll upload it tomorrow when I'm back at my pc.
Hopefully all that makes sense. Let me know if any part of it needs clarifying.

I don't appreciate the negative attitudes displayed by certain members here. It doesn't lend to constructive discussion. The only issue I've ever had with this setup is that you get ghost images where the background images are too small. To fix that just extend the canvas of these backgrounds.

EDIT: script attached