Which connie?
EDIT: Oh crap, you're right - its my connie refit. Give me 5 minutes and I'll put up v1.2
EDIT2: Okay, my $0.02 regarding the Sivista and Miranda.
The miranda is a light cruiser to me - a bigger and badder light cruiser than, say, the Kearsarge, but still a light cruiser. The sivista still feels like a heavy cruiser to me. If scaled proportionately to the Ktinga it actually seems to outmass the ktinga. I really like to think of it as a parallel ship. When the 3 ktingas in the Motion Picture swung by in that diagonal formation, for me, one of them might as well have been a Sivista their capabilities were so similar. More or less equal, but different.
That's just what my head does with the design.
Slightly confused by your kitbash request. You want a Sivista with a third nacelle on the boom, or a D5 (what on my site is called the QaHos) with a nacelle on the boom?