I had this idea, posted it in another thread about how to make crafting more relevant, and felt like, "hey, I should expand on that!"
So, we've already got Fleet Ships. That's great. But, what if we could make shuttles and fighters? Maybe for the Vault, maybe for giggles, maybe there could be more specific scenarios involving small ships (PVE and PVP)?
A ship yard (such as a fleet's or possibly even a public one?) would be needed, as well as several ways to come up with necessary components. A multi-step process, solo or via teams, could be used, to help create things like the chasis, nacelles, electronics, etc.
So, you could have a shipyard with relevant DOFF missions, crafting/work stations, bank access, a Dilithium store for various parts, etc. You'll spend time, resources, etc., to create the parts, assemble the ship, etc. In the end, individuals and teams can make ships for their own use! Things that would need to be made would be:
Lots of things that could be made and used by crafters, you know? And, if somethings can't be dropped, only made and sold? Hey...
Purely cosmetic items could be bought/created with Energy Credits or Latinum.
Unreplicatable Materials could be used instead of Dilithium.
Data Samples should have some relevance on what is being created. For instance, any physical sample could be used, but using specific ones could impact ship damage capacity, innate resistances/vulnerabilities, weight (affecting top speed), size, etc.
Having a DOFF style Critical, Success, Failure, Disaster system, with everything but Disaster being salvagable might be worthwhile.
Having an underlying "quality of integration," allowing a ship to be more than, equal to, or even less than the sum of its parts might be good. Even if the parts aren't top quality, the overall ship might be good because of how well everything is put together.
Specific missions, or even a market, could be put together to encourage ship creation. For instance, getting a rare Trade mission where someone important requests a specific type of ship would be interesting (be it for a fleet, an individual, etc).
Having the ships be automatically damagable (ie, requires starship repair components) may be a worthwhile thing, but I dunno. That might discourage people from making them. At the same time, though, that would be a fair trade-off between the purchased ships and crafted ones.