I'd say that there must be many, many more ship designs than the small handful that has been detailed in canon. There may well be a jump-2 version of the Beowulf Class and a jump-1 version of the Empress Marava. Just as the Placid Ox, Golden Gryphon, and Soaring Eagle are jump-1, -2, and -3 versions of the same hull (http://jtas.sjgames.com/login/article.cgi?792 (requires a JTAS Online subscription to see)).Any logical reason for these two to have different hull designs? I mean to say, why wouldn't someone who wanted/needed J-2 just move some interior walls and upgrade their free trader?
How to haunt the ship ...