I set my Matrox G450 to span the desktop across both monitors for an effective monitor resolution of 2560x1024.
Unfortunately, I couldn't get MA to span the monitors.
In this mode, the settings dialog only contains "Monitor 1" in the dropdown, and when it runs, only the first monitor is used for the display.
I tried to play with the widescreen and anamophic settings, but it just wouldn't go to the other monitor.
Oh well, it was worth a shot...