These four files demonstrate how FL ships that didn't ever get used by the game except in SP (such as, for example, Cruisers) could be integrated into a mod very easily, and added to Factions so that they showed up at appropriate places.  This version of the Liberty heavy fighter has been made into a heavy fighter on the verge of being a VHF... but not quite ;-)  It will show up at all areas where you'd normally just encounter Liberty Heavy Fighters, so watch out, pirates! 

In the case of the Cruisers, you'll have to make a "clone" of the Shiparch entry, change the type from CRUISER to FIGHTER, and then integrate it into the Factions, but it's not a whole lot more complicated even with that necessary step in place.  Please do not email me about this- there are several tutorials and a lot of example code on TLR about how to make Battleship Encounters, and it's a very short step from doing it via INI editing to doing it with XML :-)