The Sechat-Hor looks to be very promising, depending on the final texture design.
I'd actually make a design for your campaign with it's "Giga-Sathani" as well as a design for the standard FS2 universe where it would be a design of Emporer Khonsu kept undercover until a decade after the battle of Capella. (2382) Having it built mainly to destroy several smaller ships, while balancing it would work well. (also "Super Juggernaught?" sounds a little cheesy, I'd look for a new designation if I were you)
Also I hope that the final ship will make full use of subsystems and debris. The top outcropping near the rear of the ship could be used as the bridge, and similarly be destroyed. (also allowing for large hull sections to be blown away would be impressive)
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AceStaff member FreeSpace Watch
http://freespace.volitionwatch.com/