Unfortunately, I haven't managed to get my hands on a copy of Issue 3 of General Grievous, but when I saw the preview I couldn't help noticing the Star Destroyers (or possibly large Star Frigates) on the cover:

http://www.darkhorse.com/profile/preview.php?theid=10-578

These vessels are obviously not Acclamator-class assault ships:

-There are prominent ventral reactor bulges of the type associated with later Star Destroyers such as the Victory and Imperial classes.
-The hullform is different, being much more sharply tapered with the bow forming a sharp point similar to that seen on the Victory-class.
-The stern is different from an Acclamator. Although there is a protrusion, presumably a hyperdrive housing, it is much wider and shorter relative to the ship than on an Acclamator.

They are also clearly not Venator-class Star Destroyers:

-The hullform is substantially different. There are no indentations on the side to accommodate hangar bay openings.
-The command tower has only a single bridge pod.
-Venator-class ships lack a reactor bulge.

Similarly, the vessels are obviously not Class II Frigates (sisterships of the Rand Ecliptic):

-The Class II Frigate does not have a ventral reactor bulge, these vessels do.
-The Class II Frigate has four prominent hangar bays, two on each side of the lower hull. As noted above, these vessels have no visible hangar bay.
-The command tower structure is visibly different, the Class II Frigate having small bridge wings hinting at the configuration of the standardised command deck used on the Imperial, Tector and Executor classes.
-The Class II Frigate's hullform on the underside forms a deep V-cross-section keel, this class is much flatter on the underside.

And finally, we can rule out Victory-class Star Destroyers:

-The command tower is the old "Rothana" style, whereas the Victories had a command tower similar to, but different from, the style later adopted by KDY.
-Again, there are no hangar bays. VicStars have hangar bays. (I'm sounding like a broken record here, aren't I? )
-The aft hyperdrive housing is absent from the VicStar, but this class clearly has one, or at least a similar type of structure at the stern.
-And finally, this design lacks atmospheric manoeuvring surfaces on the sides of the hull, a prominent feature of the Victory-class design.

Conjecture:

The characteristics of this design suggest to me a specialised Star Destroyer specifically designed for ship-to-ship combat and orbital bombardment. The main reason for this is the conspicuous lack of major hangar bays, which would obviously preclude the planetary assault/transport and fighter-carrier secondary roles of most Star Destroyer designs. As an aside it's possible that this design may have been a direct predecessor to the Tector-class, which also lacks major hangars and may have a similar mission profile. Although I should note that I mean this in operational terms, rather than design lineage, since the Tector-class appears to have been a rather straightforward conversion of an Imperial-class hull.

At any rate, I need to get my hands on the actual comic itself, because there could be something important I'm missing here.

30/10/05, EDIT: Corrected inaccurate reference to underhull reactor bulge on Venator-class.