I don't think that they were ever announced in this ES. We have colonization ship, scout ship (same appearance as one small ship), 2 small ships, 2 medium ships and 1 big ship - carrier (and there is ark for vodiani). Have you seen anywhere more ships in context of ES 2?

There are, for the most part 6 Different hull types of ships for each major race;

Civilian/colonization----------Corvette-----------Destroyer--------Cruiser-----------Battleship----------Dread/Carrier (different terminologies are used in various places) I am sure they will be able to fill either role adequately

there are different roles for hulls of the same type; scout, (or better yet you make your own )things like that, (i think) i dont remember at this moment.