Since this is the only thread that I found searching for defensive ships, going ahead and posting here. Now that the game is out, and I have played through around 10 games total, I think this is an area that could be addressed, either in an official patch or a player mod.
Right now, the best defender that I seem to get is the BattleAxe, which is the 2nd, IIRC, military ship that I can normally build (right after Defenders). In the beginning of the game they do a decent job defending, by the end of the game 10-20 of these on a planet is normally enough to level up the attacking ship, but do nothing for defense.
Are there better defending ships out there in the tech tree? I don't like the idea of building battleships and overlords for defense; I think it would be great if there were advanced defenders as technology rises.
What do you think?