I've not done any FREDding but I have been improving my loadout code recently. Most of the basic idea is already in HEAD but I've been refactoring the code to make it better and adding new features as they came to me. Once I'm done you'll be able to buy and sell ships and weapons if you make a "shop" mission.
With some clever FREDding you could have a home base(s) with selection of ships you'd bought and choose which one you flew on any mission. You could then use that for whatever you wanted to (e.g. Narn ships have problems in Centauri space but no one starts a fight with a Nial since they're worried about starting another war with the Minbari). You could even do an Elite and have a First One fighter on some distant planet no one will ever visit.
More clever SEXping you could allow you to only repair ships on their own species' bases or places like B5.
I'm going to have to look into whether it's possible to make the loadout code work on a per ship basis as that would allow al kinds of other fancy tricks (hiring wingmen for instance).
So as far as I'm concerned the idea isn't dead. I'm just doing behind the scenes stuff on it.
Whether I'll ever get round to FREDding anything is another matter.
To be honest though I'm not worried about trading that much. I'd be working on something like Freelancer without the trade. You fly from system to system doing missions to raise cash instead.