The Campagnolo Catalogue No. 17 from 1974 (the hardback one) had a Campy triple set up that way, not sure what the original middle ring was, item No. 1049/3 on page 72. I agree with Lou Deeter about why anyone would wish a set up like that with a front low of only 42 teeth.
Happy trails,
Dan Artley, with a Campy Strada crank converted to 74 mm bolt circle diameter for a real granny, in Parkton, Maryland