Tipster Tomek sent us a note about his friend Zbijmnie of EU Vek'nilash, to see if, at level 49, he might be one of the lowest level players to every hit the goal of 100,000 honorable kills for the achievement, but after looking around for a bit, I've found the achievement is pretty commonplace. Because the count actually started way back when HKs were first added to the game (and not when achievements were), lots of people have picked up the seemingly gigantic number already. In fact, here's a level 19 who did it right when he logged into the expansion for the first time (which means he had killed 100,000 people even before patch 3.0.2.
Which is kind of a shame -- after Gears of War's "Seriously" achievement (to kill 10,000 enemies) was met, they added a "Seriously 2.0" to the sequel (to kill 100,000 enemies), and that one's been met as well.
So in retrospect, getting 100,000 HKs isn't too hard -- even if you got one every second, it'd really only take you about a day of playtime, which is probably a lot less than a month of realtime, depending on how long you play for and how good a player you are. Maybe in the next achievement update we'll see a really impossible goal for players to work on: 10 million mobs killed? 10,000 instances run? A million players looted in the battlegrounds? There's got to be something in the game that seems impossible for someone crazy out there to work on.