OK, I'll stab at it... but bear with me, I'm a bit st*ned at the moment.
ARe you familiar with the Pauk class Patrol Boat addon? Included with the mod is a script, which allows the vessel to use two independent weapon mounts, that works very well. That's the key to this thing... The script enables a seperate vehicle, modeled as a man in an static machine gun mount ( AK-630 naval CIWS:
http://www.naval-technology.com/projects/zubr/zubr3.html ) to move along as a part of the ship model. As I stated before, it works VERY well. Your Slava class missile ( CRUISER, not frigate. Why didn't you just ask for a Kirov class nuclear battlecruiser!?! LOL! ), would be done the same way, but on a much larger scale, you would use one man to each arm one of the ships weapon systems. In this way, any ground based weapon system in game, including missile systems, could be modelled. Whats more, by utilizing one of the scripting tricks, available around here, that allows one player to control four or so squads, at a time, could even make this even cooler... Like the C and C mod, this addon- if done right- could be one of those rare addons that actually transform the entire nature of gameplay, in OFP.
Anyway, I don't see why all possible weapon possibilties including large, multi-cell verticle launch sytems, and multiple close in weapons mounts like the Phalanx, and Kashstan.
The maker of the Pauk class is your Yoda, Obi Wan... go to Degobah, and seek him out...
May the Force be with you.