Oooo ooooh a CR2 rumor for the 100-400L MkII. Where have I seen one of those before? Oh, yes...it was way back in October, 2010.
In the meantime, I've missed so many shots like this:
Yeah well... How about this CR3 from 2008??
Canon EF 100-400 f/4-5.6L IS [CR3]
JUNE 27, 2008 CANON LENSES
The source that spoke of the 5 new lenses from Canon claims the 100-400 is indeed getting an upgrade. It'll be slightly faster and possess a 5 stop IS. He wasn't sure whether or not it would be a push/pull design or not.
Canon EF 100-400 f/4-5.6L IS = $1899 USD