24-70L focusing

I hope to order the 24-70L within the next few weeks after much delibration about the alternatives. These forums were an immense help in my selection process.
Could someone please clarify an issue with regard to the structure of the Canon lens. The 17-40L and 70-200L which I already have do not change length while focusing or zooming. This is one of the features I like about these lenses.
From reports it seems that the 24-70L is different and the length of the lens reduces with longer focal length. My question is does the front element rotate? This would make using a polarising filter difficult.

Yes this lense does increase in size at the shorter end of it's zoom, however the front element does not rotate so a circular polarising filter is no problem.

One really slick thing about the way the 24-70mm f2.8L works is related to the lens hood. It's a good sized, deep lens hood. You'd think that it would not allow wide angle work. However, the lens gets longer at the wide-angle end, so it comes out closest to the front edge of the hood at 24mm and deepest into the hood at 70mm. This is fantastic, as the hood is able to provide great protection from stray light as well as from physical contact with things.

With the lens hood fitted it does not protrude past it.

As Skip rightly points out the hood protects the lens over ALL it's zoom changes - it really is a monster of a hood, comparable to those on the big zooms for length, in fact almost as long as the length of the lenses shortest physical size.