And HL2 works in portrait mode. Hard to play tho. The levels are definitely not designed for that kind of view. Sins of a Solar Empire wouldn't let me set the resolution to 1200x1920. it runs, but it's distorted.
I think the solution will be two landscape monitors in the middle, one above the other, with two portraits on the sides. we'll see. Might hafta build something.
edit: something like this: