my 2 cents -
1) Baskin Robbins is certified by Star-K for all but 1 (recently 2) flavors. which means they trust the protocol of washing the scoop sufficiently, or it's not really treif, just has treife gelatin in the marshmallows or whatever.
2) Same is true for Stone Cold Creamery, IIRC (but it's been years.
3) Krispy Kreme doughnut mix is all certified. its mixed with water and fried in each store separately. Obviously, the oil would have to be kosher. there are a number of stores with local certification in the LA area and elsewhere. (agav, a fun place to take kids, really cool conveyer belt through the deep frier / glazer etc., Also really good doughnuts).