Sitefinity 4.0 *NOT* pushed back to 2011
Well, good bye 2010 it seems :/
After seeing the functionality in the initial CTP it probably was a bit optimistic to think it would be out this year.
So as you can see by the comment below here, looks like christmas is coming early for developers!
*UPDATE 2* Nov 11 2010
Official release date of January 14th, 2011