From Tatiana’s TOMATObase:
In growing out Brandywine in 1997 (from seed saved in 1993), Craig LeHoullier noted a number of regular leaf seedlings. Unsure if this was a cross or mix up, he grew out one plant, which produced large, oblate pink fruit with distinct vertical gold stripes - a very unusual result.
Assuming therefore he was looking at an F1 hybrid, he undertook growouts of saved seed over the next few years. The most promising produced large, smooth oblate bicolored fruit on a potato leaf plant with superb flavor. With a working name of Rainbow Brandywine, Craig was joined in stabilization efforts by a nearby North Carolina seed saver, Larry Bohs. Eventually the selection neared stabilization and Craig named it Lucky Cross. A second selection, essentially a smaller, rounder version with similarly excellent flavor, was also stabilized and named Little Lucky.
In looking over his garden map of 1993, the experimental variety Tad grew nearby. (Tad was a variety named by Carolyn Male for seed saver and amateur breeder Tad Smith - it is the result of an effort to get a Tigerella type striping on large fruit with a bicolor interior. He started with a cross that included Old German with Tigerella. Tad ended up being a medium sized, nearly round yellow fruit with distinct gold stripes. It is nearly certain that Tad is indeed the source of the striped characteristic of the crossed Brandywine seed.)