tldr; There's some information out there that the GT3e chip (which will presumably be used in the 2013 13' rMBP) supports 4K video output.
Source - http://www.tekrevue.com/2013/05/02/intel-details-haswell-gpus-brands-high-end-gt3e-iris-pro/
Here's the $1600USD question though - does this mean you can use the rMBP in conjunction with a 4K display?
Source - http://www.tekrevue.com/2013/05/02/intel-details-haswell-gpus-brands-high-end-gt3e-iris-pro/
Here's the $1600USD question though - does this mean you can use the rMBP in conjunction with a 4K display?