Over at the German site for the Canon CPN network, we can see the Canon EF 11-24mm f/4L listed. This lens has been previously rumoured, but no announcement date has been set. We've heard the price for this lens will be around $2899 USD and it will be a stellar performer.
The Google Translated text reads
“The EF11-24mm 1 : 4L USM is the longest ultra wide -angle zoom lens for Volformat cameras by Canon . It is characterized by the completely new design , new lens coating and its unrivaled performance .”