Does anyone else feel that removing the arbitrary hull sizes and going with something a bit more fluid would make a change for the better?
Miniaturisation tech (or it's equivalent), engineering tech, material tech and structural integrity tech could all play a part in how much 'mass' you design a ship to use.
You could also in theory shape manufacturing around increasing mass production capacity per turn and then in turn being able to 'spend' it to build any number of ships with it per turn (provided you have enough mass for it) or just focusing it on one big project.