You know, now that I think about it, what I'd love to see is a Ki-100.
It was basically a ki-61 airframe but with a powerful and reliable radial engine, and two cannon and two MG. Later models were purpose-built for the radial, and had a bubble canopy. What resulted was, to, again, quote wikipedia because all my books are at home:
"The Ki-100 was soon encountered in combat by Allied forces, and it was rated by them as a first-class combat machine. A well-handled Ki-100 was able to out-maneuver any American fighter, and was (more or less) equally fast to them, specially at medium altitudes. In one encounter over Okinawa, one Ki-100-equipped unit destroyed 14 Hellcats without losses to themselves.[citation needed] The Ki-100 was also able to match the P-51D Mustangs and the P-47N Thunderbolts which were escorting the B-29 raids over Japan by that time, and in the hands of an experienced pilot, it could defeat them (the Army's Ki-84 and the Navy's Kawanishi N1K-J being the only other types able to achieve this). Against the B-29s themselves, however, things began to get difficult for the Japanese fighters, as the engine's performance decreased at high altitudes."
"Although slow in level flight for 1945, Ki-100 could dive with P-51 Mustangs unlike most Japanese fighters and hold the speed on pullout. The cannons had 250 20x94 mm rounds/gun, each projectile weighing 112 g (armor-piercing) or 79 g 12% high explosive. Muzzle velocity was 700 (730 HE) m/s (2,300 ft/s; 2,400 ft/s) giving an effective range of 900 m (2,950 ft). The 850 rounds/min firing rate decreased by roughly 27% when synchronized through the propeller. Still, it remained fast enough (620.5 rounds/min) even by Western standards. The wings carried 250 12.7x81 mm rounds/gun. Each machine gun bullet weighed 35.4 g AP (33-38 g 2.2%HE) and had a muzzle velocity of 760 m/s (770-796 HE) (2,450 ft/s; 2,500-2,600 ft/s) giving an effective range of 750 m (2,460 m). Rate of fire was 900 rounds/min. Unlike nearly all other Japanese military aircraft, the Ki-100 was not given an allied codename, a very glaring omission considering that the aircraft was frequently encountered in combat during the last months of the war."
This also seems like most of the work is done, in the form of the KI-61 we already have...
-Llama
