Many years ago circa 1968/9 I had a 1964 Alfa Romeo 1600 Giulia Sprint - it had rotten front wings, rear panel & sills they were really bad for rusting.(I did buy it cheap - but it became a money pit)
The cost of replacement new parts was just daft beyond words, I found a local coachbuilder who took off the old wings and made new ones using some sort of hand operated roller, likewise the sills & rear panel were fabricated. When done it looked like factory replacements. Admittedly some of the original metal remained - he used lead to fill any joints where new met old.
Believe it or not the front and rear bumpers even had holes in them- I had them repaired & rechromed due to stupid parts prices.
I have lost my photos from the time but this was the shape - mine was metallic gold. They were full of modern specifications such as independent suspension all round, 5 speed gearbox, cruise control ( hand throttle type) twin webbers, disc brakes all round, reclining front seats etc.
alfa by
Ted Bagshaw, on Flickr