I thought I remembered there being a 3.5 prestige class that combines the abilities of monk (e.g. unarmed damage increase) and rogue (sneak attack). I can't seem to find it in the books, though. Can anyone point out the name of this class, and what book it's in, if it does, in fact, exist? D&D 3.5 or Pathfinder sources, please (I think it's from 3.5).
In the Dungeons and Dragons 3.5 Index - Prestige Classes it lists the Master of the South Wind which is a rogue/monk combination prestige class that is in Dragon Magazine 314 p35.
Also there is the Monk of the Long Death in the Players Guide to Faerun p65 but not sure if that is as good a match.
While not being a prestige class, this feat does the trick.
ASCETIC ROGUE - Prerequisites: Improved Unarmed Strike, sneak attack. Benefit: When you use an unarmed strike with a sneak attack to deliver a stunning attack, you add 2 to the DC of your stunning attempt.
For example, a human 5th-level rogue/1st-level monk would deal 1d8 points of damage with her unarmed strike.
Also, "If you have levels in Rogue and Monk, those levels stack for the purpose of determining your unarmed strike damage." Complete Adventurer page 106.