No me neither mate! Ive only fought them on the outskirts of cities, like around stables and whatnot and they LOVE the college of winterhold. The big cities are considered as interior cells in this game and i dont believe dragons can maneuver convincingly in such closed spaces, oh the lag if they did though..... Still i may yet be surprised.
Man, those hired thugs always turn up at the wrong time!! I was on my way to use Farengars enchanting table once, walked in and a bloody thug was using it! And his mate was busy creating poisons to kill me at the lab next door. (no really, they werent just standing there, they were busy crafting away)
Turned out old farengar wasnt pleased about me stealing his two soul gems while he was sleeping and had decided to take out a hit on me.
This is actually a testament to radiant story people, those thugs that come to kill you actually visit the person who takes out the hit to collect the contract first! Very clever.
I've dealt with one, inside Solitude. Didn't have the problem with the corpse sticking around for too long as some have mentioned. It happened near the slope that leads to Castle Dour. Pretty bad place for a dragon to choose to swoop down on, considering the number of Imperial guards nearby.