The following lenses have been slated for announcement from a few sources.
EF 35 f/1.4L II USM
– availability in the summer
EF 80-400 f/4-5.6L IS USM
– avalability in the summer
We know the 35L replacement is coming, I was initially told it would be in the fall of 2009. Expect a long delay on purchasing the lens after announcement.
As for the 80-400, this is the first time I've heard about this focal range for the replacement of the 100-400. Take this with a bigger grain of salt than the 35L II.
No info about a 24-70 replacement with IS.