Silent Assassin

Turned last quest while mounted, did not get achieve, watch out.

Make sure that you dismount before you turn in the final quest for the day or you will NOT get credit for the achievement!

I've had to do this three times on the beta to figure this out. The first time I didn't get it and thought it was strange, so the second time I kept a close eye on everything and I noticed that when I turned in the final quest I got an error "You are mounted". So today for the third try I dismounted before turning in the quest and got the achievement.

No idea why it wants you to dismount, it looks like the quest giver casts a spell on you when you turn in the final quest but it doesn't seem to actually do anything.

This is the beta, so it may well be fixed before MoP goes live.

I earned the achievement with the following quests.
A Morale Victory
The Bigger They Come...
Sra'vess Wetwork
Fumigation

and the final Quest:
Target of Opportunity: Sra'thik Swarmlord

Those five quests seems to be called the "Wu Kao" Set.

I also dismounted before I turned in the last Quest.

Tip/Hint: You should not pick up a Shado-Pan companion since s/he could kill one additional add which would ruin the achievement.
Also, doing a whole set of Shado-Pan dailies without a companion is part of the achievement Loner and a Rebel.