Apple could sure get one of these displays. I don't know whether it would use IGZO, though, as I read somewhere color reproduction is not very good on these displays.
There's also a 35W quad-core option that might fit the 13" rMBP. The 35W quad-cores use an HD4600 video card, though.
Right, it's the HD 4600 that makes things complicated.
There are a lot of options for ULV processors with HD 5000 graphics, so I would guess Apple would want to use those. An Air with HD5000 and a Pro with HD 4600 doesn't make much sense.