It's been brought to my attention that Gallic Brigands should be smuggling Human Organs, but it's not profitable because of your rule that if anyone can legally haul it, it's balanced like a legal commodity.
I have an idea for a solution.
Untagged Human Organs. Human organs with no proper medical history, no paperwork certifying their sourcing, etc. Just some Brigands dragging some poor bastard into an alley and leaving with his kidney. Logically it follows that this commodity would never be legal.
It's most in-demand on planets with a sizable underclass - people who need the transplants but can't afford legitimate attention. Pittsburg is a good example. Nearby smuggler stopover hubs such as Rochester would also offer a decent price.
Current Human Organs would remain as-is, with perhaps a tweak to the infocard noting their legal sourcing. It would still make sense to limit their transport; the safe transport of human organs would almost certainly require special equipment and proper knowledge, so House laws wouldn't have to change much if at all. One thing that would change, however, is that certain unlawful bases would have an inflated price. While pirates are generally willing to make do with whatever, they're willing to pay a bit more on the rare ocasion they get something they can actually be sure is safe. A good example of this sort of base is Buffalo, as no one that can legally carry Human Organs in Liberty can land on Buffalo.
This leaves the question of "is a new commodity worth it?", and I believe the answer is yes. As I said in the first line, this should be an important thing for the Gallic Brigands, and would be a way to give them some flavor to distinguish them from other unlawful factions. Slaves go in, organs come out, you can't explain that.
