At their NAB Show press conference Grass Valley have announced they are making a 4K Native B4 lens LDX camera. Trials of the camera available this North American Summer.
Along with a 4K workflow solution, Grass Valley also showed the LDX XtremeSpeed 6X (360 fps) ultra-slow-motion camera which is currently being trialed with Root Sports and Lyon Video. No official release date or price as of yet.
Vine video via @TVBroadcast
Screen grab via Director De Fotografia.