Monkey Paw is one of the more exotic styles in the game. In fact, there's only a single opponent who uses it. You will have to have to fight him twice, though. So you have a double chance of learning it. You may also be able to buy this style.
The opponent I'm talking about is Sung Bo - one of the contestants in the gold level of the Imperial Arena. You can buy Monkey Paw from merchant Shipeng in Tien's Landing after finishing the main quest in that area.
I suppose the reason, why Bioware did not make this style available to players, is that they thought it's overpowered. It's fast and does a lot of damage. It doesn't have a lot of reach, but since you can throw yourself at your opponents like a cannon ball, that doesn't truly matter. So, yes, it's overpowered. Or rather: It was. The bad news is, that I had to re-balanace it a little. The speed is the same, but it does a bit less damage now. But I did increase the walk speed to compensate.
Martial Style This style can complete a Harmonic Combo. Being based upon the movements and mannerisms of the monkey, Monkey Paw utilizes acrobatics and lightning fast strikes to dispatch opponents before they have chance to act. It's very fast, unpredictable and deadly.
Fighting weapon styles with a martial style is tricky, but Monkey Paw's speed makes it quite feasible: