Ever since Star Wars: The Old Republic was announced, it was a sure thing that we'd see the Hunter Killer assassin droids in the game, and indeed Bioware has released a teaser trailer announcing the appearance of HK-51, a few models down the line from everyone's favorite meatbag-loathing machine, HK-47.
Presumably, the droid will appear in the game as a player companion, though how he'll be unlocked for characters isn't yet apparent. The trailer mentions an ancient ice base where
"scores" of "the most dangerous machines in the galaxy" exist, so there will likely be a bit of story and questing to go through to find this model and use it.
And let us be clear: You had better go get that droid, meatbag.