I, too, am very disappointed in the lack of support for NVIDIA surround / AMD Eyefinity. This technology has been around for a long time now and I wish developers would pay more attention to it.
If the Gearbox developers have never played a game on 3 monitors they are missing out. Just go right now and steal some monitors from the marketing department and try it. Load up Bioshock Infinity, for instance. That game does it right. When marketing comes to find their monitors, they will see how great it is and insist that you support it properly. in all games so they can brag about it and show it off in demos.
After all, is it really that much work to detect a super-wide resolution and adjust the UI to keep it on the center screen? Or just include a setting that lets the user manually define a region for the UI to appear in. Would that be hard? It already stretches to fill the available area, just let us define what that area would be.
I know this is not the most common setup, but I would bet its more common than 4K right now. It is not a “driver thing”, it is a UI thing. Please do consider patching this.