i have experimented with the thought of making a supermassive "explorer" type vessel that uses one of the ship types with no limit in size. it would basically return to its home system only every few in game years to refit to any new changes or designs it needs to continue its mission.
but i cant remember if that got patched out or not.
anyways, shark, if your curious what kind of ships each race would build, you will just have to use your imagination.
i could imagine atuuk being likely to never build ships much larger than destroyers, preferring to swarm an enemy.
i can imagine the securan being unable to engage in any real kind of war, preferring to retreat under all but the most overwhelming circumstances, preferring long range battles and just downright surrender.
some races i always laugh at when i see tho, like the naxxilian, falling usually meant t-rexes died, it must be embarrassing for them when they go into space, maby thats why in all my games they never have more than a half dozen worlds.