Yeah, this almost matches what I always assumed a pre-refit/2270s-80s Miranda would look like. The nacelles would be very close to if not identical to those of Consitution ships and the impulse engines and engineering would be where they are comparable to post-refit designs.
We'll be seeing a pre-refit Miranda-type vessel (the U.S.S. Copernicus) in the upcoming Star Trek New Voyages/Phase II episode "Blood and Fire")--written and directed by David "The Trouble with Tribbles" Gerrold.

Greg Schnitzer
Gaithersburg, Maryland