I've finally found a really good 'grape tomato'. Plants are very productive and rather tall, too (6 foot +). Classic flavor, with a hint of sweetness.

HISTORY: I obtained my original seed from Trudi Greissle Davidoff, owner of WinterSown.org. The label stated:  "Saved by a loving daughter, these are yummy grape tomatoes, nice for salad or snacking, IND, 72+ DTM".
 
I reached out to Trudi asking for more details and this is what she said: "The only information I have is the name I gave the seeds. If I recall right they were sent with a note about that they reseeded in her Mom's garden and that they were something they always looked forward to. I want to say Indiana or Ohio but can't remember, I don't have the correspondence anymore."
 
Sold in a 3.5" pot.