I didn't even think they were in yet... but I looked it up, and it seems they ARE in. I know I need to talk to the "Penguin Bay: Illegal Goods" trader at the Outpost, and from what I've read the only prerequisite is that you have to have repaired the FTL drive in your ship, which I have. But for some reason, I still can't talk to the guy. I try clicking on it and nothing happens.
Finish the other quests at the outpost. I didn't even realise I could do that until after I had Cerulium Armour and I was just cleaning up the last few quests, only to discover that ship upgrades were a thing.
Nope, normaly the Penguin Bay trader should sell you the first upgrade after Erchius, providing you finished all the side quests given by the other guys at the outpost. The upgrade will then unlock an other set of side quests at the outpost wich will lead to the next upgrade, wich will unlock the next set of quests, etc, etc.