No--I am simply making a "shell". After flying the barge, I realize that if the interior is left empty it is adequate size. The slow maneuver and long time to cruise make it ideal for this sort of thing and actually give a purpose to the ship. Later, if someone wants to make dockable ships--these will already fill the bill. As to guns--those things can be decided later. My goal here is realized by the fact that the barge is the largest possible ship. Anything larger can't dock or fit through things easily. Using the cylindrical hull for the base size makes it practical to hitbox a "one size fits all approach. The Hispania and some of the bases already have "fly though" hit box designs so we know it is possible. Superstructure can be added on a faction by faction need basis and will be eye candy only anyway. The barge also allows for superstructure room already too.
The idea is simple--keep mostly the barge stats--though the spin will HAVE to be dealt with. Cargo bays can be reduced so no abuse is made by them. To launch fighters, simply import a cargo bay (and size it up as needed) from one of the vanilla ships and jettison cargo to "open the launch bay". The slow speed and maneuver of the barge allows fighters to fly "in" it and I don't know if forming and screwing with model parameters will work well enough to make it practical.
It takes skill to fly a barge and it will take skill to fly in one. Its actually quite rewarding and fun.
So chime in experts. I did want to actually make the model and get the glory but honestly its worth having it done well and I'd prefer to see it made and used over simply getting kudos. Start with the barge size cylinder and hit box it. Add an enlarged, operable bay door from a vanilla ship. The spin HAS to be fixed though--its not gonna work otherwise. Make it with a smallish cargo capacity.
The barge stats at present make it easily a ship you could "fly inside". I'd recommend keeping the current speed and maneuverability (ha ha). Give it monster hit points and some guns and it would be fearsome with ships inside. Varying bay door sizes could determine "ship classes" even.