The Teradek Cube WiFi camera link is claimed to be "the first of its kind, a camera-mounted HD network video encoder."
It captures live video directly from the camera, encodes it using H.264 and streams it over WiFi or Ethernet (up to 1080 23.98/24/25p or 50/59.94/60i, 720 50/59.94/60p) using IP. Bitrates are selectable between 250Kbps and 10Mbps.
It uses very little power, only 2.5 Watts, and can be powered by any 12v camera battery. It comes in several versions, with or without WiFi, and with HDMI (particularly suitable for use with HD DSLRs, which typically only have HDMI output) or HD-SDI/SDI input, with prices ranging from $1,490 to $2,190.
It can be mounted to the tripod screw under small video cameras for handheld operation, between the base of the camera and the tripod or to a hot shoe or rail system. Control and video monitoring is via a web user interface, viewable on any browser.
It would be useful for remote monitoring on set, where users could see the camera feed on a laptop, mobile phone or iPad, or for wireless recording from remote mounts (including in-vehicle cameras) or Steadicam systems. Or it could be used for live news feeds from anywhere in range of a WiFi connection. However, delay is about one third of a second over WiFi so probably not suitable for interviews.