If I remember correctly, the Prophets that originally set out from their homeworld on the forerunner dreadnought(High charity) went to war with the Elites after drifting around in space. So I would assume all the covenants ships and vehicles are elite based designs(Save for the brute stuff). This is just off the top of my head speculation though, someone else can probably find a more concrete argument.
The Forerunner Dreadnought is only the pyramidal ship, the rest of High Charity was built by the covenant (if I remember correctly).
Also, it is said that the Sangheili-San 'Shyuum war was basically divided in two parts: the field war, where the Sangheili had the upper hand, and the space war, where Forerunner tech used by the San 'Shyuum helped them defeating the Sangheili; thus I would assume that most of Covenant's ship are San 'Shyuum design. This is huge speculation, though.
Anyway, I'm really, really excited for this novel. The artwork is amazing, and I always wanted clarifications on the rise of the Covenant.
Peter Jackson, 27/07/2013: 1.08 am. A 20 hour day ... 15 years of Tolkien ... 771 days of shooting ...
"We would be fools to pursue the impossible simply because you believe the achievable is flawed" - Ugin