I stumbled across the blurb in the fluff for the Imperial Wolfbanes Iron Bolas:
"Such weapons have been seen elsewhere in the Solar System, mostly used by the much-feared Slavers of the Marauder Confederation."
Was there a pirates faction that never got created or were these a Dark Eden tribe? Sounds like a question for "Warzone: In Search Of" with Nenord Lemoy. Or maybe Prime. I'm guessing he's still busy with taxes though.