Licensing issues will prevent most of the Canadian stations from being shown on Dish/Directv. Most if not all the programs they carry are already licensed to other stations in the States.
For instance, almost everything on Space is under license in the States for Sci-fi & Spike. Dish would be required to black out every one of those shows in order to show the channel here. Or Space would have to contract to be able to show them here, which is unlikely as then the owner would have to reduce the fee that Sci-fi & Spike pay to them.