If not the P61, How about the A26 Invader?
Almost as fast, Just as well armed and can carry a load almost on par with the B17.
A26-B 6,000 lbs internally with later models upgraded for an additional 2,000 lbs on wing racks or rockets.
Would make a real nice strike aircraft.
A26 Invader has always been one of my favorite medium bombers. Used to see them all the time doing tanker drops for the forestry service during wild fires.
