Quite some time ago I suggested that Nikon needed to produce a video-only camera, what I called the V1. Nikon did produce a V1 and it does do remarkably good video, but it isn't a video-only camera.
Canon, meanwhile, got the message: today they announced Cinema EOS and the first of what are likely to be multiple large sensor video cameras based on their existing lens mount (you can get it in PL mount, too). The result looks a bit like some alien tinkerer hacked up an EOS 1D, but it's most definitely a video camera, not a hybrid still/video camera. Almost exactly what I suggested Nikon do (it's missing a higher than 1080P format, though).
Meanwhile, RED finally announced Scarlet is shipping. So here we have two high-end and highly anticipated large sensor video cameras and they come in Canon or PL lens mounts. Hollywood's love for F-mount lenses is coming to an end, apparently, and it isn't Hollywood's fault.