Via tsrjoe. Also Special Projects Forum.
Lockheed Model L-255, In 1953 CALAC proposed to the RCAF a modified Constellation 1049D for maritime recon. The Connie airframe was modified with a nose-mounted 20-mm gun turret, increased cockpit windows, added search radar, added external pod for gunner, stores, radar and camera, added MAD tail and added wing rockets and missiles provisions. Internal changes would be minor except as necessary for the new equipment.
Performance would have been a bit less than the Model 1049D due to the added protuberances creating additional drag. The idea was to have turboprop power plants to restore performance levels. (Note: which would have reduced range)
Retractable dorsal turret visible on the forward fuselage in the side view