Wouldn't it be cheaper, faster and more versatile to develop a new breed of stealth cruise missiles instead? They are already somewhat stealthy, they are far simpler pieces of kit and they can be launched from a variety of platforms of various sizes, from any part of the world (Sea, land and air). I suspect they could even develop man portable versions, where the missle and launch rails break down into something that a SpecOps team could carry into enemy territory to extend range or reduce the journey time.