A replacement to the 17-40 f/4L?
Apparently a patent for an EF 16-40 f/4L IS will be filed soon and I'm told to keep an eye for it over the next couple of weeks.
The 17-40 is one of the best values in “L” lenses and is a cash cow for Canon. It does need improvements on the edges and Nikon stabilized their f/4 full frame wide angle. It's a believable replacement.