So it would be pointless to make it that large. While it would be nice, it causes more issues than solutions. 1100 seems to be the max without issue. if you start seeing black squares as you run around bleed over into your gameplay screen. lower it more.
You could max out the screen size and be like Erza... pretending the black pixel glitches that come from it are just the fog of war, like Starcraft!
currently use 1980 x 1350, i can see way too much, but i like to put bags, player status bars/monster bars, rune books, etc in the corners. I do notice the black squares when i run around, i've got so used to it, but now i know why. I'll try turning it down and give-r hell.
Many people don't know this but having too many icons,bags,gumps etc can actually slow down your client refresh speed in terms of millisecond speed. Performance is best with nothing but the game window. I'm not making this up. This is actually why another replacement for razor had a spellbar icons. so it wasn't the client showing the icons but that program.