We don't seem to have a Canberra ideas and inspiration topic so I hope no one objects to me using this one.
How about a fighter version of the Canberra, not just radar fitted etc. but more along the lines of the Hornet vs the Mustang, or the Cobra verses the Huey?
Canberra wings and engines with a narrow diameter fuselage, tandem cockpit, radar, cannons, etc.