Looking forward to seeing the first dragon one-shotted by a backstab on youtube.
I'm willing to bet sneak attacks, except for maybe the first sneak bow attack, are going to virtually impossible. I bet Dragons will be able to detect anyone within 10 ft regardless of your sneak ability. It's what I would do being a designer/programmer to prevent one shot stealth kills. Just pretend Dragons have true sight and there you go.
That's just a guesstimate though. We'll have to wait and see what Bethesda actually did.
I think someone mentioned a dual dagger sneak attack. Considering Oblivion example, you can't power attack while sneaking and the double strike is a form of power attack, so I don't think you can do a sneak attack with two daggers (or other weapons) at the same time.
I'm pretty sure I did power attacks for my first sneak attack every time during Oblivion. Not sure what your source is.