I bought a T3i this spring which is smaller than the 7D. Because of the flash, it wouldn't fit in a 1200, so I'm sure that you would need at least a 1300 which is going to be too big to fit well in your boat.
I ended up going with a watershed (ocoee) and have been pretty happy. It isn't a quick to open and close or protect the camera as well, but it fits between your legs no problem, and there is plenty of extra room in the bag for lunch, sunglasses, etc. Watershed also makes padded liners for the bag which helps protect things, but I just used some extra clothes and a small towel to pad things and had no problems.
I might buy a pelican for jeep/raft trips for the convenience and protection, but bottom line I would go watershed with that big of a camera in a kayak.
Life is either a daring adventure or nothing. - Helen Keller