I've played SINS using Eyefinity. The screen shot shows the answer to your questions.
The tree does appear on the far left, and the info cards appear on the far right, which can make it a bit difficult to manage the empire, as these parts of the user interface cannot be moved. It would be great if the developers would modify the interface so that these elements are relative to the central main interface, so that they wouldn't move to the edges.
Better yet, they should make the tree customizable as far as being able to move it to where you want, and resize it to more than one column. As for the info cards, it'd be nice if they where shown attached just to the lower right of the interface. I'm not sure if there is a mod out there that addresses these user interface problems for Eyefinity.
I have found that the game plays best with monitors placed in portrait mode if you have a 3x1 setup, since then, the tree has more room to expand. Too bad they can't make a tree with multiple columns.