good idea,  however will hardly ever get used.  people who up for a mission dont up with enough fuel to go 1/2 way somewhere.  besides not many people actually rearm anywhere.  some do, most just get another airplane.  and if you are talking about a long range mission, well the time it takes to land and refuel then climb back up to 20k+ will give the enemy more than enough time to get organized and shoot you down.
semp