Forget about dedicated "camera" packs
No, no, no, don't even think about buying that Canon pack or another Nikon pack or even most of the small Lowe Pro packs. These "camera" packs are totally inadequate in an active sport situation- they are made mostly to look good in the store. The worst thing about them is the harness system, it never keeps the pack close to your body and it almost always lacks a proper hipbelt. And don't even try to do any technical skiing with a heavy camera in a pack without a hipbelt!!!
In my experience there are three features that are paramount in carrying a camera while skiing:
1. A good hipbelt that keeps the pack stable
2. A good harness that keeps the pack close to your back; either the adjustable harness or a proper back length is a must.
3. Backpanel access: it is a lot easier to dump your pack on the snow, open the backpanel and get your camera without trying to balance it or without getting the pack back all wet. You would especially appreciate that on a steep slope.
As you guessed, most of the "dedicated" photo packs do not give those options, and they are awfully unstable if you try to ski anything technical with them. My current solution is an Osprey Switch26- it is a dedicated skiing pack, so it has all the bells and whistles, nice carry system and back access. The main compartment fits my SLR with 70-200 lens in a Domke insert. The front and back panels are padded, so they protect the camera reasonably well.
I also used and own a dedicated photo skiing pack- Burton Zoom. This is the only dedicted ski pack that I consider fit for skiing, and I saw pros use it at Squaw, but to me it does not add much to what Osprey does, so I don't use it. You may like that pack.
Here is a picture of a friend that I took on a day when I carried a camera in the Osprey pack.
P.S. Most serious pros I saw prefer the LowePro or ThinkTank bags, but those are huge packs that are designed to carry a lot of gear and have a full-blown backpack carry system. I am sure this is not what you are interested in.