Incidentally, I have another display idea that would be almost as good as Valerie's 3 full displays... possibly, even better, because it wouldn't require 4 feet of horizontal space: a central 3840x1440 display, flanked by a pair of double-hinged 1920x1440 displays that could fold out, forward (like window shutters) so you could close the lid, or backward (so they'd be facing the rear).

This would give you a big 3:2 primary display for things like an IDE, flanked by a pair of 3:4 displays... say, the one on the left for a pdf document or web page that's being referred to, and the one on the right for something like the Android emulator, a window for whatever is being tested/debugged, etc.

When folded against the back of the middle display, you could either turn them off (say, if you're on a plane & don't have room to open them outward), or use them as a pair of 3:4 rear-facing displays (or, if a middle seam is tolerable, a rear-facing 3:2 display).