Canon Rumors has been told that Canon could release a new 800mm in 2013. The EF 800 f/5.6L IS II lens could have a newly developed 6 stops image stabilization system. The weight is said to be less than the EF 600 f/4L IS II
Moreover, there are rumors about new supertelephoto zooms and 400mm primes. No timetable or schedule was suggested.
Finally the 1.4 teleconverter sported on the EF 200-400 f/4L IS 1.4x is said to get featured on more lenses in the future, at least the technology appears to be tested on other lenses.