For such an advanced ship I would recommend a new power source then the standard Matter/Anti-Matter reaction. I was thinking a bit of Romulan inspiration with a twist would be an order. How about a ship powered by a singularity core, except this core has two singularities orbiting around each other at a very high speed.

"The rotating motion of both singularities effectively caused them to be orbiting each other. This has actually made containing and stabilizing the singularities more efficient then what is found in any single singularity core. The rotating motion also provides more power. The only drawback to such a design was that the orbiting speed has to be strictly regulated to reflect the core's power output. In then end though, the dual singularity design proved more then adequate to provide ample power to larger vessels. Although such a core cannot be effectively downsized without losing its effectiveness as a viable power source." - Doctor Jared Samson, Daystrom Research Institute.
The core's design was a sort of idea I had when I was re-imagining a new fleet revamp project after the Federation had nearly been wiped out. It's a bit of fan fic that involves the destruction of StarFleet Command as an organization and the near complete dissolving the the Federation as a whole. The Federation won the great war with the help of the Klingons but were left completely devastated. Left with some relative peace some surviving members of the Federation began rebuilding the Federation's foundation.
In the early years of the rebuilding several of the remaining StarFleet admirals came together and began what was simply known at the time as "The New Beginning Project". The idea was to rebuild StarFleet on a completely new and fresh technological foundation. The project began with revamping the way resources are harvested or mined. The project was formed with near total secrecy with only some of the highest members of both the Federation and the Klingon Empire being aware of the research being done.
The project was founded on a burning determination to not only restore the Federation but completely revamp it. After about 10 years the project would have designed 5 new ship designs featuring all new sensors, weapons, propulsion and power systems (including the new Dual Singularity Core).
Yeah I'm just rambling on. It's a bit of a story idea I've had brewing in my head for a few years, and this would be the first time I actually speak of it to anyone else. If you guys want me to flesh the story out I could do so, but the purpose of this post was to suggest a fresh core design for DJ to work with.