If you have a DDI subscription, then your quest is over. The article "The Art of the Kill," from Monday has everything you need. In addition to being a huge, mega-article with all kinds of great content, it has rules for the garotte as a weapon and then does a "multiclass" Weapon Training feat chain for it. It gives you a series of encounter powers at various points during the heroic teir that you can substitute in for other powers. They're pretty cool and definitely go a long way toward making the garotte a valid weapon for a certain build of stealthy PCs. Eventually, you get the Body Shield ability just like the bugbear strangler.
However, since you are asking this, I assume you don't have a DDI subscription. You should get one.