Perhaps this need some explanation. I've wondered why this kind of ship doesn't exist. Obviously with 3-4 helos, adequate sensors, 5-6 support boats and room enough for salvages should be enough to have effective SAR/Patrol vessel. I can't explain; maybe you can...
It would cost more than a Normal warship AND doesn't looks cool AND would render the surface warship officers into chauffeurs for the helicopter pilots ......
Surface warfare department would never agree (and the pilots want a full CV anyway)
BTW It would probably be more than just a OPV, with the right helicopters it would be much more powerful ASW and even ASufW than any surface warship (and the V22 might be fitted with AA missiles and a AEW set to make it a better AA ship as well ?)