Shame we never got to see this ship in the movies.

id love to see your version of this ship modelled in 3d :) looks great as is tho.

It never occured to me that this ship is a triple nacelle starship.

Thanks all. In fact this ship violates Genes pair rule, but then again it is a non Federation design, which could imply warp technology is not universal.

Are you sure the D'Deridex-Class is the three-nacelled design? I mean, we've seen a number of one, three or four-nacelled ships, even one five-nacelled (the Prometheus Class, but only in MVA mode) on Star Trek, but what we've seen on the series of the D'Deridex class ships suggests that the aft section is not actually a warp nacelle, simply because their are windows in it, and a nacelle needs to be separate from the ship's main body, unless it is screened like the Defiant, the Steamrunner and in Cardassian designs. For a view of the aft compartment of a Romulan D'Deridex class Warbird as seen in the series use this link please: http://www.cardassiaprimera.com.ar/ClaseDreidex.jpg You'll notice that there are so many windows at the stern that there is no room left for a warp nacelle. The same image is printed in the Deep Space Nine Technical Manual, chapter 16.3, "Romulan Starships", which suggests that it can be looked upon as semi-canonical information at least, and I think in the episodes featuring beauty shots of the Warbird or in those fleets during the Dominion War we've seen a number of Warbirds that do have these window details, after all, the number of windows is an important indication to allow judging the size of this thing, after all, the D'Deridex class is HUGE compared to all other designs except Borg vessels or the ridiculous Scimitar seen in Nemesis.

You are quite correct. There is no canonical evidence to support the existence of a third nacelle. At the time I made these schematics, I used to base the caption information on the Fact Files schematics and no other source.