Prior to the release of the latest Canon EF 24-70mm f/2.8L II lens, there were rumors that a prototype of a version with Canon’s Image Stabilization was undergoing testing. Then, the new lens came along, it didn’t have IS, and word of any kind of possible replacement with image stabilization died out.
A recently published Canon patent document reveals that Canon has, in fact, developed such a lens. This lends credibility to reports of a prototype version in the wild. Additionally, we can further speculate about whether or not Canon would deliver such a lens to market in the future. (I know a lot of Photography Bay readers would love to see a Canon EF 24-70mm f/2.8L IS lens on the front of their EOS bodies.)