As much as I love Hendo, I think Fedor would maul him. Hendo has a great chin but Fedor hits like a freight train. Plus Fedor's subs are really good and he pulls them off with surprising technique and speed!
Hendo is realistically one of my favorite fighters and has been since his run in Pride, but he has less of a chance of beating Fedor than most of the guys he's fought and Hendo would not be Fedor's greatest challenge in my humble opinion.
Never the less, I'd still want to see them fight