It's a draft!

I didn't remember that the designation was visible in the picture, lol!
Anyway, oh Mighty Master, although your challenge seemed to be impossible to win, I didn't give up.
It's a S.A.I. 403!

Only one prototype was built, MM.518, the one drawn in the picture above. It's a 1943 aircraft, powered by the Isotta Fraschini Delta RC.40, that never was an affordable engine.
EDIT:it seems that the prototype was captured by the Nazi, after the Armistice, as I found this picture on the net
