Didn't North Americam produce a civilian version of the Mustang, Merlin-engined, after WW2, called the Cavalier?
http://http://en.wikipedia.org/wiki/Cavalier_Mustang
Edit-should have done some simple homework first. More to it than I thought.
Edit again--Was the late Bill Wylie's twin seat Mustang a Cavalier or a "proper" USAF training variant? I had the pleasure of flying it ICUS as a 5oth birthday present to myself. Highlight of my logbook, after my first solo and Basic Aerobatics endorsement.