There were a few of these rebodied lightweight cars with 356 pushrod box and running gear
I think a lot of people worked out that the 550 and RS60 and 61 were successful because of good running gear , brakes and lightness ....so they just added some more lightness
There were also some "Poopers" Porsche coopers which I personally think look even better where thee driver sat in the middle of the car ... (Some of the RS60s also had a moveable setup so the driver could sit in the middle)
Anyway , heres a modern pic of one; actually 2 ...the one in the background is also a porsche cooper...
http://images.google.co.uk/imgres?imgur ... -QaB1syPAw
Vintage pic with mechanic sitting in jumpseat ...This one does have a 4 cam
http://images.google.co.uk/imgres?imgur ... -QaB1syPAw
Heres a page with the 550 and the pooper racing the same day
http://images.google.co.uk/imgres?imgur ... -QaB1syPAw