From an email posted to Baen's Bar Honorverse dated September 24, 2004:

System defense ships

    System Defense Ships. The idea here, as I understand it, is to build a very big, very nasty ship -- sub-light only, I think -- which would be unmanned in combat. I'm not entirely sure whether the consensus finally settled on running them by remote control from manned ships accompanying them or relying solely on souped-up AI to do the job. In either case, there would be no protoplasmic crew aboard the ships which would make them more expendable. And, a possible side benefit (if I'm remembering correctly) would be that they could be built big enough to rely on grav plates rather than inertial compensators and still turn out a decent acceleration rate because there would be no squashable human personnel aboard, which would allow them to absorb much higher gee forces. I believe it was suggested that they would normally operate with minimal manned crews -- essentially only engineering personnel -- between combats, and that those skeletal crews would be removed when battle was joined. Presumably, this would even further reduce life-support requirements and free up still more space to be used for weapons, defenses, or electronics warfare capabilities. Is this a doable concept?

     

    System Defense Ships. The concept has crossed my mind. I doubt anyone will ever build them. Again, it's bells and whistles time. You're buying a whole passel of additional things that can go wrong when you rely that heavily on automation. I'm not saying that the idea is totally impractical; it simply saying that I don't see any of the admiralties in the Honorverse investing the kind of money and materials it would take to build these things in any sort of reasonable numbers when they would have strictly limited utility and flexibility. It makes much more sense, I think, to build ships which still incorporate human crews… and which have complete all-around capabilities as a result. Yes, it would be nice to have ships which would be totally expendable, but the fact of the matter is that whether they are crewed or not, a ship the size you're talking about would be a significant portion of the military capabilities of whoever owned it. As a result, it wouldn't really be "more" expendable (in the cold, hard calculus of combat) simply because you would not lose two or three hundred human lives when the ship was destroyed. And any advantages which you gained in size, expendability, higher acceleration for a given tonnage, etc., would probably be more than offset by the loss in the responsiveness and/or capability which a trained onboard human crew confers. Opinion may vary on that, but since my opinion is the one which is going to guide the ship design choices made by the Manticorans, and since no one else would have the technical capability to build these things at this time, anyway, I think you can pretty safely assume that you aren't going to see them in the novels.