I’VE ALWAYS LIKED THIS CONCEPT: Should the U.S. Navy Turn Merchant Ships into Floating Missile Magazines? “For the price of one new destroyer with 96 missile silos it could easily have up to 30 ex-commercial vessels with 50 missiles each. One destroyer can only be in one place at a time, but 30 ex-commercial vessels could be in 30 different places all over the globe.”
I had some related thoughts here.