I think the 24-70mm f/2.8 L IS will come eventually. However, it will be in a price point well above the 24-105. The 70-200mm line (with an f/2.8, an f/2.8 IS, an F/4, and an F/4 IS version). Just because Canon makes an f/2.8 version of the lens in the same focal length, it doesn't seem to diminish the demand for the f/4 versionssignificantly enough to stop production.All the lenses fill a niche, and the reason everyone doesn't get the f/2.8L IS is because of its hefty price tag. Therefore, if anything, the additional f/4 lenses do nothing but increase overall sales by giving the more budget conscious consumers an obtainable lens.


In the same way, I don't think the introduction of a 24-70mm f/2.8 L with IS will severely diminish the sales of the 24-105 f/4 L, as long as it carries a premium pricetag (as it justifiably will).


On a side note, the whole reason I purchased a 7D instead of the 5D Mark II is because the 24-70mm f/2.8 L IS didn't exist. I fell in love with the general purposefunctionality of my 17-55mm f/2.8 IS, and I couldn't bear to leave any of its useful traits (the focal range coupled with IS) on the table when upgrading to a full-frame camera. When Canon does come put IS into their 24-70mm f/2.8 L, I will once again evaluate an upgrade.