gotta agree with Schizm on that.
With all ones creativity you should be able to make a completely original ship which looks good. It also might be part of cause I make all my ships for a role playing server, inwhich star wars or wwII ships don't very well compliment the freelancer universe. Though if someone planned on making a complete star wars conversion say maybe using the Rebellion map then such ships would fit into that universe. Or for the wing commander ships to be put into a compele conversion of the freelancer universe to privateer maps and bases. The difference would be in terms of the mod being just a ship package, or a complete conversion which just uses freelancer as the game platform for it.
In the end, when making ships one needs to consider how they are going to be applied. And what preconceptions the players have toward those ship designs when using prexisiting models, and how to apply them so as to compliment the preconceptions which people have and not rewrite them.