RE: Looking for a recipe from "Seafood Shanty"
Believe it or not, I believe I know what kind of dressing you're talking about. First of all, you have to remember that in those days in "sweet 'n' sour" Berks County, Italian dressing bore no resemblance to its South Philly cousins.
And no, MzLiz, you weren't hallucinating; it did have purple flecks. During the 80's, paper packets of coleslaw dressing mix were available in the produce sections of the grocery store. The ingredients were usually dehydrated and finely chopped onions, carrots and RED CABBAGE, along with celery and dill seeds, powdered buttermilk, pepper and lots of salt and MSG. The buyer added mayonnaise, sour cream or a combination of the two, cider vinegar, sugar and cabbage. I remember the directions saying to add less sugar and wine vinegar instead of the cider vinegar to make Creamy Italian Dressing. About the mid-90's, they seemed to have dropped the red cabbage with its resulting purple flecks but otherwise I would imagine the taste would be about the same.
I would start by checking for powdered coleslaw mixes and see if that starts to take you in the right direction.