The long awaited Canon EF 200-400mm f/4L IS 1.4X super telephoto lens rumored to be announced along with EOS 7D Mark II. Canon may be introduced both product together in one big event.
Canon EF 200-400mm f/4L IS 1.4X Super Telephoto lens made an appearance at NAB Show 2013. Canon is waiting for the manufacturing process to be finalized so production can begin. The expected launch date is Fall, 2013. According to the rumors same release date with the Canon EOS 7D Mark II DSLR camera.
The weight of this lens is pretty close to the EF 600mm f/4L IS II. Canon EF 200-400mm f/4L IS 1.4x price expected to be over $10,000 as rumored before.
As for Canon EOS 7D Mark II will have a brand new sensor, probably rumored in-production 21 MP or previously rumored 24MP sensor. More specs for the new EOS 7D MK II can be seen here.