Marry in haste...
While an all-civvy solution is clearly not on, is there not a case for a mixed fleet? That's certainly something that Boeing feels is on the cards for some operators (with P-8 + their Challenger-based MSA).
You can do a lot with a small, low-op-cost platform with modern technology (displays, processors, sensors and satcoms all deliver more bang for the lb, W and cu ft than they used to) - and why launch a Vulcan-sized, $200 million, mil-speced warplane every time some Chichester-wannabe gets in over his head, or a bunch of herring-bandits intrudes on the EEZ?
I hope someone's considering the ups and downs of that approach...