Hi folks,
Yep, if you want the latest Canon Rumors you can get them direct from Canon, at least so far as high end kit is concerned.
The latest example is the
EF 24-70mm f/2.8L II USM. Announced in February it was slated for summer delivery (Park Cameras still quote July on their web site as I write) but Canon Rumors are now
reporting that the lens won't ship until mid September.
This seems to be a recurrent pattern from Canon. Examples: EOS 1D X (shipping months late), the EF 600mm and 500mm F/4L IS II USM (announced in Feb 2011 and only started shipping
this month 
) and now the EF 24-70mm f/2.8L II USM.
To be fair some recent lenses have shipped on time. The EF 24mm f/2.8 IS USM and EF 28mm f/2.8 IS USM are examples though neither are "L" lenses. It's also true that the earthquake/tsunami and floods won't have helped but I don't think the timings support those natural disasters as being the sole cause. Rather it seems that Canon is now prepared to pre-announce ultra-expensive kit months and sometimes a year or so ahead of availability. Does this matter? I guess that's very much up to the individual customer.
I've added a poll. No doubt there are other possible reasons but I hope I've identified the three most likely possibilities.
Bob.