The other thing that the 1.4 spec adds is the 4096×2160p24 frame format. Not something that will be used right away, but that's why the extra bandwidth is built in. I have a feeling we'll see an HDMI 1.5 or higher before we get 4k displays.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris