Try the University of Minnesota's recent release,'Petite Jewel'. Very
fruity, almost perfumed flavor, and seedless grapes don't get any hardier.
Not to get picky, but Petite Jewel was made from a cross done by Elmer
Swenson. It is hardy to about -32F or so, small berry on a small cluster,
but is just wonderful to eat; spicy, explosive fruit flavor.