Good news if true. I wonder why f/4 if there's no IS? Just to make it lighter I suppose?
I'm guessing IS may become difficult to add with very wide lenses were aliment becomes very exact, plus I'd argue that with no filter thread it naturally becomes a bit more of a "tripod" lens as landscape users will probably either be merging exposers or using very large filters for more dynamic range.
Admittedly, I'm a little dissapointed about it being only f/4. DOF isn't an issue at this focal length, but for astrophotography and low-light photos, if it had been the rumored f/2.8, the extra light would have been quite welcome.
Of course, I'm assuming this is real and not a prank.
There have been rumours about such a zoom for awhile but looking at it the front element does look quite close to the Canon 14mm 2.8 so it could be a photoshop merger of that and say the 16-35mm IS.
I wouldn't be supprized if we saw such a lens as an F/4 though and instead an update of the 16-35mm F/2.8, the latter just seems like a more natural range from an F/2.8 lens as well as likely being easier to create.