The Mitsubishi KI-109 was based on the KI-67 "Peggy" bomber airframe. I was meant to be a high altitude B-29 bomber destroyer. Only 22, plus 2 prototypes were built. The cannon sticking out the front was a 75mm meant to fire at the B-29 from a distance, so the KI-109 was safe from the bombers defensive weapons.
This is the LS kit. It was actually a pretty nice kit.
The decals were slightly out of register, but I don't normally build Japanese aircraft, so I didn't have spares.