There's no question that the classic PC stealth game Thief: The Dark Project was a big influence on Arkane's masterful new game Dishonored.
The folks at Gamefront are up to their usual tricks tracking down easter eggs and references, and have found this just lovely Thief reference in one of Dishonored's later levels. I don't think there are any significant story spoilers in here, though it is from one of the third-act levels.
I'll have to keep an eye out for this on my second playthrough. I just played that part of Thief for the first time a few weeks ago!
Dishonored: How to Find the Thief Easter Egg [Gamefront]